diff --git a/sql/migration.sql b/sql/migration.sql
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index 0000000..1944fe8
--- /dev/null
+++ b/sql/migration.sql
@@ -0,0 +1,637 @@
+-- ============================================================================
+-- PROCUREMENT + INVENTORY SCHEMA v2.6 — PostgreSQL Migration
+-- Integrated ER: Material → Supplier → Category + PM arrival flow + inventory
+-- ============================================================================
+
+BEGIN;
+
+-- ============================================================================
+-- EXTENSIONS
+-- ============================================================================
+
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";   -- for gen_random_uuid()
+
+-- ============================================================================
+-- ENUMS
+-- ============================================================================
+
+CREATE TYPE quote_status AS ENUM (
+    'offered',
+    'accepted',
+    'arrived',
+    'rejected',
+    'expired'
+);
+
+CREATE TYPE termsheet_status AS ENUM (
+    'offered',
+    'accepted',
+    'rejected'
+);
+
+CREATE TYPE material_status AS ENUM (
+    'active',
+    'discontinued',
+    'draft'
+);
+
+CREATE TYPE attribute_data_type AS ENUM (
+    'number',
+    'integer',
+    'string',
+    'enum',
+    'boolean',
+    'date'
+);
+
+CREATE TYPE discount_type AS ENUM (
+    'none',
+    'percent',
+    'fixed'
+);
+
+CREATE TYPE item_decision_status AS ENUM (
+    'pending',
+    'chosen',
+    'rejected'
+);
+
+CREATE TYPE quote_event_type AS ENUM (
+    'offered',
+    'accepted',
+    'rejected',
+    'arrived',
+    'note',
+    'edited',
+    'expired'
+);
+
+-- The exact 10 supported inventory transaction types (no generic OTHER).
+CREATE TYPE inventory_transaction_reason AS ENUM (
+    'PURCHASE',
+    'WITHDRAWAL',
+    'RETURN',
+    'TRANSFER_IN',
+    'TRANSFER_OUT',
+    'DAMAGE',
+    'WASTE',
+    'LOSS',
+    'FOUND',
+    'STOCK_COUNT'
+);
+
+-- Casdoor-backed roles. NULL = provisioned but not yet assigned.
+CREATE TYPE user_role AS ENUM (
+    'pm',
+    'procurement_manager',
+    'admin'
+);
+
+-- ============================================================================
+-- USERS & IDENTITY
+-- ============================================================================
+
+CREATE TABLE users (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    casdoor_id  TEXT        NOT NULL UNIQUE,
+    first_name  TEXT        NOT NULL,
+    last_name   TEXT        NOT NULL,
+    phone       TEXT,
+    role        user_role,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- ============================================================================
+-- CATALOG DOMAIN
+-- ============================================================================
+
+-- ---------- UNITS ----------
+CREATE TABLE units (
+    id          INTEGER     GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    code        VARCHAR     NOT NULL UNIQUE,
+    name_fa     VARCHAR,
+    dimension   VARCHAR,  -- length, mass, pressure, area, volume, voltage, count, ratio, time, currency
+    si_factor   DECIMAL     NOT NULL DEFAULT 1.0,
+    is_base     BOOLEAN     NOT NULL DEFAULT FALSE
+);
+
+-- ---------- BRANDS ----------
+CREATE TABLE brands (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    name        TEXT        NOT NULL,
+    country     TEXT,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
+    CONSTRAINT  uq_brands_name_country UNIQUE (name, country)
+);
+
+-- ---------- MATERIAL CATEGORIES (the 8 FIXED topic categories) ----------
+-- Seeded by init_db / seed_stack with slugs:
+--   mechanical-installations-pipes, electrical-equipment-supplies,
+--   doors-windows-glass, metals-steel-sections, construction-materials,
+--   construction-chemicals, finishing-interior-decoration,
+--   construction-tools-equipment
+-- The app NEVER auto-creates categories.
+CREATE TABLE material_categories (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    slug        TEXT        NOT NULL UNIQUE,
+    name        TEXT        NOT NULL,
+    description TEXT,
+    is_active   BOOLEAN     NOT NULL DEFAULT TRUE,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- ---------- ATTRIBUTE DEFINITIONS (Global Attribute Dictionary) ----------
+CREATE TABLE attribute_definitions (
+    id              UUID                NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    attribute_key   TEXT                NOT NULL UNIQUE,
+    label           TEXT                NOT NULL,
+    data_type       attribute_data_type NOT NULL,
+    unit_id         INTEGER             REFERENCES units(id) ON DELETE RESTRICT,
+    enum_values     JSONB,              -- Allowed options for enum types
+    created_at      TIMESTAMPTZ         NOT NULL DEFAULT now()
+);
+
+-- ---------- CATEGORY ATTRIBUTES (Junction) ----------
+CREATE TABLE category_attributes (
+    id                      UUID      NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    category_id             UUID      NOT NULL REFERENCES material_categories(id) ON DELETE CASCADE,
+    attribute_definition_id UUID      NOT NULL REFERENCES attribute_definitions(id) ON DELETE CASCADE,
+    is_required             BOOLEAN   NOT NULL DEFAULT FALSE,
+    is_filterable           BOOLEAN   NOT NULL DEFAULT FALSE,
+    conditional_rules       JSONB,    -- UI Wizard rules
+    sort_order              SMALLINT  NOT NULL DEFAULT 0,
+    CONSTRAINT uq_category_attribute UNIQUE (category_id, attribute_definition_id)
+);
+
+-- ---------- MATERIALS (GLOBAL catalog entities — v2.5) ----------
+-- category_id is NULLABLE and DERIVED automatically from the first linked
+-- supplier (supplier_materials insert, first-link-wins). name is GLOBALLY
+-- unique (uq_material_name). topic is a legacy display column no longer
+-- written by the app.
+CREATE TABLE materials (
+    id                UUID            NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    category_id       UUID            REFERENCES material_categories(id) ON DELETE RESTRICT,
+    name              TEXT            NOT NULL,
+    topic             TEXT,           -- LEGACY display column
+    canonical_unit_id INTEGER         NOT NULL REFERENCES units(id) ON DELETE RESTRICT,
+    status            material_status NOT NULL DEFAULT 'active',
+    created_at        TIMESTAMPTZ     NOT NULL DEFAULT now(),
+    updated_at        TIMESTAMPTZ     NOT NULL DEFAULT now(),
+    CONSTRAINT uq_material_name UNIQUE (name)
+);
+
+-- ---------- BRAND MATERIALS (M:N Junction) ----------
+CREATE TABLE brand_materials (
+    id           UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    brand_id     UUID        NOT NULL REFERENCES brands(id) ON DELETE CASCADE,
+    material_id  UUID        NOT NULL REFERENCES materials(id) ON DELETE CASCADE,
+    catalog_code TEXT,
+    is_active    BOOLEAN     NOT NULL DEFAULT TRUE,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT now(),
+    CONSTRAINT uq_brand_material UNIQUE (brand_id, material_id)
+);
+
+-- ---------- MATERIAL UNITS (Packaging / Unit Overrides) ----------
+CREATE TABLE material_units (
+    id                UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    material_id       UUID           NOT NULL REFERENCES materials(id) ON DELETE CASCADE,
+    brand_material_id UUID           REFERENCES brand_materials(id) ON DELETE CASCADE,  -- NULL = generic fallback
+    unit_id           INTEGER        NOT NULL REFERENCES units(id) ON DELETE RESTRICT,
+    conversion_factor NUMERIC(18,6)  NOT NULL,  -- Multiplier → canonical_unit_id
+    is_default        BOOLEAN        NOT NULL DEFAULT FALSE,
+    CONSTRAINT uq_material_unit UNIQUE (material_id, brand_material_id, unit_id)
+);
+
+-- ---------- MATERIAL ATTRIBUTE VALUES (Typed EAV) ----------
+CREATE TABLE material_attribute_values (
+    id                      UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    material_id             UUID           NOT NULL REFERENCES materials(id) ON DELETE CASCADE,
+    attribute_definition_id UUID           NOT NULL REFERENCES attribute_definitions(id) ON DELETE RESTRICT,
+    value_number            NUMERIC(18,6),
+    value_string            TEXT,
+    value_boolean           BOOLEAN,
+    value_date              DATE,
+    CONSTRAINT uq_material_attr_value UNIQUE (material_id, attribute_definition_id)
+);
+
+-- ============================================================================
+-- QUOTATION & PROCUREMENT DOMAIN
+-- ============================================================================
+
+-- ---------- SUPPLIERS (1 supplier → exactly 1 category) ----------
+-- The old suppliers.categories JSONB (array of category names, added at
+-- runtime by init_db) is DROPPED in v2.6 — replaced by category_id.
+CREATE TABLE suppliers (
+    id              UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    name            TEXT        NOT NULL,
+    category_id     UUID        NOT NULL REFERENCES material_categories(id) ON DELETE RESTRICT,
+    location        TEXT,
+    phone           TEXT,
+    contact_person  TEXT,
+    tax_id          TEXT,
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_suppliers_category_id ON suppliers(category_id);
+
+-- ---------- SUPPLIER MATERIALS (NEW — the direct supplier↔material edge) ----------
+-- Auto-created whenever a quote line item is saved; managed via
+-- /suppliers/{id}/materials and /materials/{id}/suppliers.
+CREATE TABLE supplier_materials (
+    id                UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    supplier_id       UUID           NOT NULL REFERENCES suppliers(id) ON DELETE CASCADE,
+    material_id       UUID           NOT NULL REFERENCES materials(id) ON DELETE CASCADE,
+    is_active         BOOLEAN        NOT NULL DEFAULT TRUE,
+    last_quoted_price NUMERIC(18,4),
+    last_quoted_at    TIMESTAMPTZ,
+    created_at        TIMESTAMPTZ    NOT NULL DEFAULT now(),
+    CONSTRAINT uq_supplier_material UNIQUE (supplier_id, material_id)
+);
+
+CREATE INDEX idx_supplier_materials_material ON supplier_materials(material_id);
+
+-- ---------- PROJECTS (1 project → 1 PM) ----------
+CREATE TABLE projects (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    name        TEXT        NOT NULL,
+    description TEXT,
+    start_date  DATE,
+    pm_user_id  UUID        REFERENCES users(id) ON DELETE SET NULL,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- ---------- QUOTES ----------
+CREATE TABLE quotes (
+    id              UUID         NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    supplier_id     UUID         NOT NULL REFERENCES suppliers(id) ON DELETE RESTRICT,
+    project_id      UUID         REFERENCES projects(id) ON DELETE SET NULL,
+    quote_date      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    expiry_date     DATE,
+    accepted_date   TIMESTAMPTZ,
+    arrived_date    TIMESTAMPTZ,
+    status          quote_status NOT NULL DEFAULT 'offered',
+    is_official     BOOLEAN      NOT NULL DEFAULT TRUE,  -- TRUE = formal; FALSE = estimate/draft
+    notes           TEXT,
+    created_at      TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    updated_at      TIMESTAMPTZ  NOT NULL DEFAULT now()
+);
+
+-- ---------- QUOTE EVENTS (Audit / History Log) ----------
+CREATE TABLE quote_events (
+    id          UUID             NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    quote_id    UUID             NOT NULL REFERENCES quotes(id) ON DELETE CASCADE,
+    event_type  quote_event_type NOT NULL,
+    payload     JSONB            NOT NULL DEFAULT '{}',
+    occurred_at TIMESTAMPTZ      NOT NULL DEFAULT now(),
+    actor       TEXT
+);
+
+-- ---------- LINE ITEMS ----------
+CREATE TABLE line_items (
+    id                UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    quote_id          UUID           NOT NULL REFERENCES quotes(id) ON DELETE CASCADE,
+    material_id       UUID           NOT NULL REFERENCES materials(id) ON DELETE RESTRICT,
+    brand_material_id UUID           REFERENCES brand_materials(id) ON DELETE SET NULL,
+    unit_id           INTEGER        NOT NULL REFERENCES units(id) ON DELETE RESTRICT,
+    quantity          NUMERIC(18,4)  NOT NULL,
+    notes             TEXT,
+    created_at        TIMESTAMPTZ    NOT NULL DEFAULT now()
+);
+
+-- ---------- LINE ITEM SPECS (Historical Snapshot) ----------
+CREATE TABLE line_item_specs (
+    id                      UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    line_item_id            UUID           NOT NULL REFERENCES line_items(id) ON DELETE CASCADE,
+    attribute_definition_id UUID           NOT NULL REFERENCES attribute_definitions(id) ON DELETE RESTRICT,
+    value_number            NUMERIC(18,6),
+    value_string            TEXT,
+    value_boolean           BOOLEAN,
+    value_date              DATE,
+    unit_id_at_time         INTEGER        REFERENCES units(id) ON DELETE SET NULL,
+    CONSTRAINT uq_lineitem_spec UNIQUE (line_item_id, attribute_definition_id)
+);
+
+-- ---------- TERMSHEETS ----------
+CREATE TABLE termsheets (
+    id              UUID             NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    quote_id        UUID             NOT NULL REFERENCES quotes(id) ON DELETE CASCADE,
+    label           TEXT             NOT NULL,
+    status          termsheet_status NOT NULL DEFAULT 'offered',
+    discount_type   discount_type    NOT NULL DEFAULT 'none',
+    discount_value  NUMERIC(18,4)    NOT NULL DEFAULT 0,
+    created_at      TIMESTAMPTZ      NOT NULL DEFAULT now()
+);
+
+-- ---------- TERMSHEET SCHEDULE STEPS ----------
+CREATE TABLE termsheet_schedule_steps (
+    id           UUID         NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    termsheet_id UUID         NOT NULL REFERENCES termsheets(id) ON DELETE CASCADE,
+    step_no      SMALLINT     NOT NULL,
+    due_date     DATE         NOT NULL,
+    amount       NUMERIC(18,2) NOT NULL,
+    note         TEXT,
+    CONSTRAINT uq_termsheet_step UNIQUE (termsheet_id, step_no)
+);
+
+-- ---------- ITEM TERMSHEETS (Line Item Pricing in a Termsheet) ----------
+CREATE TABLE item_termsheets (
+    id             UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    line_item_id   UUID           NOT NULL REFERENCES line_items(id) ON DELETE CASCADE,
+    termsheet_id   UUID           NOT NULL REFERENCES termsheets(id) ON DELETE CASCADE,
+    unit_price     NUMERIC(18,4)  NOT NULL,
+    min_order_qty  NUMERIC(18,4),
+    CONSTRAINT uq_item_termsheet UNIQUE (line_item_id, termsheet_id)
+);
+
+-- Convenience VIEW: total_price = unit_price × line_items.quantity
+CREATE VIEW item_termsheets_with_total AS
+SELECT
+    it.id,
+    it.line_item_id,
+    it.termsheet_id,
+    it.unit_price,
+    it.min_order_qty,
+    (it.unit_price * li.quantity)::NUMERIC(18,2) AS total_price
+FROM item_termsheets it
+JOIN line_items li ON li.id = it.line_item_id;
+
+-- ---------- ITEM DECISIONS (1:1 with line_items) ----------
+-- project_id: the SINGLE purchased project, picked by the procurement
+-- manager when the item is chosen (auto-filled when the offer had one
+-- project; validated against line_item_projects). Warehouses of this
+-- project are the only valid arrival destinations.
+CREATE TABLE item_decisions (
+    id                       UUID                NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    line_item_id             UUID                NOT NULL UNIQUE REFERENCES line_items(id) ON DELETE CASCADE,
+    chosen_item_termsheet_id UUID                REFERENCES item_termsheets(id) ON DELETE SET NULL,
+    status                   item_decision_status NOT NULL DEFAULT 'pending',
+    project_id               UUID                REFERENCES projects(id) ON DELETE SET NULL,
+    adjusted_unit_price      NUMERIC(18,4),
+    adjusted_notes           TEXT,
+    decided_at               TIMESTAMPTZ
+);
+
+-- ---------- ITEM RECEIPTS (1 item : N receipts — partial deliveries) ----------
+-- The UNIQUE on item_decision_id is REMOVED in v2.6. A receipt means the
+-- PM confirmed this delivery. received_qty is in the line item's unit;
+-- inventory posting converts to the inventory row's unit.
+CREATE TABLE item_receipts (
+    id               UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    item_decision_id UUID           NOT NULL REFERENCES item_decisions(id) ON DELETE CASCADE,
+    confirmed_by     UUID           NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    received_at      TIMESTAMPTZ    NOT NULL DEFAULT now(),
+    received_qty     NUMERIC(18,4)  NOT NULL,
+    on_time          BOOLEAN,
+    quality_note     TEXT
+);
+
+CREATE INDEX idx_item_receipts_decision ON item_receipts(item_decision_id);
+
+-- ============================================================================
+-- INVENTORY DOMAIN (fork's shipped model, with fixes)
+-- ============================================================================
+
+-- ---------- WAREHOUSES (1 warehouse → exactly 1 project) ----------
+CREATE TABLE warehouses (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    project_id  UUID        NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+    name        TEXT        NOT NULL,
+    description TEXT,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- ---------- ITEM RECEIPT ALLOCATIONS (NEW — PM's split into warehouses) ----------
+-- App rule: SUM(quantity) = item_receipts.received_qty and every
+-- warehouse.project_id = item_decisions.project_id.
+CREATE TABLE item_receipt_allocations (
+    id           UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    receipt_id   UUID           NOT NULL REFERENCES item_receipts(id) ON DELETE CASCADE,
+    warehouse_id UUID           NOT NULL REFERENCES warehouses(id) ON DELETE RESTRICT,
+    quantity     NUMERIC(18,6)  NOT NULL CHECK (quantity > 0),
+    CONSTRAINT uq_receipt_warehouse UNIQUE (receipt_id, warehouse_id)
+);
+
+-- ---------- INVENTORY (current stock snapshot) ----------
+-- FIX (vs fork): brand_id is nullable, so the unique index uses COALESCE —
+-- a plain unique index would allow duplicate stock rows for unbranded
+-- materials (Postgres treats NULLs as distinct).
+-- specs_hash = SHA256 of sorted canonical specs JSON ('default' when empty),
+-- computed server-side on every write.
+CREATE TABLE inventory (
+    id          UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    warehouse_id UUID          NOT NULL REFERENCES warehouses(id) ON DELETE CASCADE,
+    material_id UUID           NOT NULL REFERENCES materials(id) ON DELETE RESTRICT,
+    brand_id    UUID           REFERENCES brands(id) ON DELETE SET NULL,
+    quantity    NUMERIC(18,6)  NOT NULL DEFAULT 0 CHECK (quantity >= 0),
+    unit_id     INTEGER        NOT NULL REFERENCES units(id) ON DELETE RESTRICT,
+    specs       JSONB          NOT NULL DEFAULT '{}',
+    specs_hash  TEXT           NOT NULL DEFAULT 'default',
+    updated_at  TIMESTAMPTZ    NOT NULL DEFAULT now()
+);
+
+CREATE UNIQUE INDEX uq_inventory_stock ON inventory (
+    warehouse_id,
+    material_id,
+    COALESCE(brand_id, '00000000-0000-0000-0000-000000000000'),
+    specs_hash
+);
+
+CREATE INDEX idx_inventory_warehouse_material ON inventory (warehouse_id, material_id);
+
+-- ---------- INVENTORY TRANSACTIONS (full chronological ledger) ----------
+-- quantity is SIGNED: positive = increase, negative = decrease.
+-- STOCK_COUNT: recorded_qty/physical_qty + quantity = difference.
+-- A transfer = two linked rows (TRANSFER_OUT + TRANSFER_IN) sharing
+-- transfer_pair_id.
+-- receipt_allocation_id links an auto-posted PURCHASE back to its
+-- allocation — UNIQUE prevents double-posting the same delivery.
+CREATE TABLE inventory_transactions (
+    id                    UUID                         NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    inventory_id          UUID                         NOT NULL REFERENCES inventory(id) ON DELETE CASCADE,
+    warehouse_id          UUID                         NOT NULL REFERENCES warehouses(id) ON DELETE RESTRICT,
+    receipt_allocation_id UUID                         REFERENCES item_receipt_allocations(id) ON DELETE SET NULL UNIQUE,
+    transaction_type      inventory_transaction_reason NOT NULL,
+    quantity              NUMERIC(18,6)                NOT NULL,
+    recorded_qty          NUMERIC(18,6),
+    physical_qty          NUMERIC(18,6),
+    transfer_pair_id      UUID,
+    performed_by          TEXT,
+    transaction_date      TIMESTAMPTZ                  NOT NULL DEFAULT now(),
+    note                  TEXT,
+    created_at            TIMESTAMPTZ                  NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_inventory_tx_inventory_date ON inventory_transactions (inventory_id, transaction_date);
+CREATE INDEX idx_inventory_tx_warehouse_date ON inventory_transactions (warehouse_id, transaction_date);
+
+-- ============================================================================
+-- INDEXES (additional performance indexes beyond PKs / UNIQUEs)
+-- ============================================================================
+
+CREATE INDEX idx_quotes_supplier_status ON quotes(supplier_id, status);
+CREATE INDEX idx_quotes_project ON quotes(project_id);
+CREATE INDEX idx_quote_events_quote_time ON quote_events(quote_id, occurred_at);
+CREATE INDEX idx_line_items_quote ON line_items(quote_id);
+CREATE INDEX idx_line_items_material ON line_items(material_id);
+CREATE INDEX idx_termsheets_quote ON termsheets(quote_id);
+CREATE INDEX idx_item_termsheets_termsheet ON item_termsheets(termsheet_id);
+CREATE INDEX idx_brand_materials_material ON brand_materials(material_id);
+CREATE INDEX idx_material_attr_values_def ON material_attribute_values(attribute_definition_id);
+CREATE INDEX idx_category_attrs_category ON category_attributes(category_id);
+CREATE INDEX idx_category_attrs_attr_def ON category_attributes(attribute_definition_id);
+CREATE INDEX idx_line_item_specs_attr_def ON line_item_specs(attribute_definition_id);
+
+-- ============================================================================
+-- QUOTE ATTACHMENTS (invoice / proforma files — bytes live in MinIO)
+-- ============================================================================
+
+CREATE TABLE quote_attachments (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    quote_id    UUID        NOT NULL REFERENCES quotes(id) ON DELETE CASCADE,
+    kind        TEXT        NOT NULL CHECK (kind IN ('invoice', 'proforma')),
+    file_name   TEXT        NOT NULL,
+    mime_type   TEXT        NOT NULL,
+    size_bytes  BIGINT      NOT NULL,
+    object_key  TEXT        NOT NULL,
+    uploaded_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_quote_attachments_quote_id ON quote_attachments(quote_id);
+
+-- ============================================================================
+-- RUNTIME TABLES (created idempotently at API startup by init_db.py;
+-- defined here too so fresh installs have them from the start)
+-- ============================================================================
+
+-- M:N quotes ↔ projects (an offer can be about several projects)
+CREATE TABLE quote_projects (
+    quote_id   UUID NOT NULL REFERENCES quotes(id) ON DELETE CASCADE,
+    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+    PRIMARY KEY (quote_id, project_id)
+);
+
+-- M:N line_items ↔ projects (offer-side allocation; the PURCHASED project
+-- is the single item_decisions.project_id)
+CREATE TABLE line_item_projects (
+    line_item_id UUID NOT NULL REFERENCES line_items(id) ON DELETE CASCADE,
+    project_id   UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+    PRIMARY KEY (line_item_id, project_id)
+);
+
+-- One reference unit per category (units dashboard)
+CREATE TABLE category_reference_units (
+    id          UUID        NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    category_id UUID        NOT NULL UNIQUE REFERENCES material_categories(id) ON DELETE CASCADE,
+    ref_unit    TEXT        NOT NULL,
+    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- Brand-scoped / category-scoped conversions
+CREATE TABLE unit_conversions (
+    id          UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    category_id UUID           NOT NULL REFERENCES material_categories(id) ON DELETE CASCADE,
+    brand       TEXT,
+    from_unit   TEXT           NOT NULL,
+    to_unit     TEXT           NOT NULL,
+    factor      NUMERIC(18,6)  NOT NULL,
+    updated_at  TIMESTAMPTZ    NOT NULL DEFAULT now()
+);
+
+CREATE UNIQUE INDEX uq_unit_conversion
+    ON unit_conversions (category_id, COALESCE(brand, ''), from_unit, to_unit);
+
+-- Global conversions, applies to all categories
+CREATE TABLE standard_conversions (
+    id         UUID           NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
+    from_unit  TEXT           NOT NULL,
+    to_unit    TEXT           NOT NULL,
+    factor     NUMERIC(18,6)  NOT NULL,
+    updated_at TIMESTAMPTZ    NOT NULL DEFAULT now(),
+    CONSTRAINT uq_standard_conversion UNIQUE (from_unit, to_unit)
+);
+
+-- ============================================================================
+-- UPDATED_AT TRIGGER (auto-set updated_at on row modification)
+-- ============================================================================
+
+CREATE OR REPLACE FUNCTION set_updated_at()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = now();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER trg_material_categories_updated_at
+    BEFORE UPDATE ON material_categories
+    FOR EACH ROW EXECUTE FUNCTION set_updated_at();
+
+CREATE TRIGGER trg_materials_updated_at
+    BEFORE UPDATE ON materials
+    FOR EACH ROW EXECUTE FUNCTION set_updated_at();
+
+CREATE TRIGGER trg_quotes_updated_at
+    BEFORE UPDATE ON quotes
+    FOR EACH ROW EXECUTE FUNCTION set_updated_at();
+
+CREATE TRIGGER trg_quote_attachments_updated_at
+    BEFORE UPDATE ON quote_attachments
+    FOR EACH ROW EXECUTE FUNCTION set_updated_at();
+
+-- ============================================================================
+-- AUTOMATION TRIGGERS (v2.5 + v2.6)
+-- ============================================================================
+
+-- Derive materials.category_id from the FIRST linked supplier (first-link-wins).
+-- Idempotent: only touches rows where category_id IS NULL.
+CREATE OR REPLACE FUNCTION fn_derive_material_category()
+RETURNS TRIGGER AS $$
+BEGIN
+    UPDATE materials
+    SET category_id = (SELECT category_id FROM suppliers WHERE id = NEW.supplier_id),
+        updated_at  = now()
+    WHERE id = NEW.material_id
+      AND category_id IS NULL;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER trg_supplier_materials_derive_category
+    AFTER INSERT ON supplier_materials
+    FOR EACH ROW EXECUTE FUNCTION fn_derive_material_category();
+
+-- Sync supplier_materials.last_quoted_price / last_quoted_at when an item
+-- decision becomes 'chosen' (INSERT or UPDATE — the accept-quote flow
+-- inserts decisions directly as 'chosen').
+CREATE OR REPLACE FUNCTION fn_sync_last_quoted_price()
+RETURNS TRIGGER AS $$
+BEGIN
+    IF NEW.status = 'chosen' AND NEW.chosen_item_termsheet_id IS NOT NULL THEN
+        UPDATE supplier_materials sm
+        SET last_quoted_price = COALESCE(NEW.adjusted_unit_price, it.unit_price),
+            last_quoted_at    = now()
+        FROM item_termsheets it
+        JOIN line_items li ON li.id = it.line_item_id
+        JOIN quotes q       ON q.id  = li.quote_id
+        WHERE it.id = NEW.chosen_item_termsheet_id
+          AND sm.supplier_id = q.supplier_id
+          AND sm.material_id = li.material_id;
+    END IF;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER trg_item_decisions_sync_price
+    AFTER INSERT OR UPDATE OF status ON item_decisions
+    FOR EACH ROW EXECUTE FUNCTION fn_sync_last_quoted_price();
+
+-- NOTE: inventory.quantity is maintained by the SERVICE layer
+-- (inventory_service.apply_transaction) with SELECT ... FOR UPDATE row
+-- locks — NOT a trigger — so the ledger and the snapshot can never be
+-- double-applied. Arrival auto-posting (POST /pm/receipts) goes through
+-- the same service path and is idempotent via receipt_allocation_id.
+
+COMMIT;