feat(observability): phase-1 silent pipeline recorder + phase-0 Jev validation

Phase 0 — Jev validated with the real key (5 Persian scenarios, api.typesafe.ai): stale project name «منشیانه»->«منشانه» conf 0.73 (ambiguity band), STT spelling variants «مصطفوی/مستفدی/مسطفی»->«بازرگانی مصطفوی» conf 0.93, exact «دفتر» 0.88, proper _none rejection for «کاغذ A4» 0.92, and two mentions in ONE request (0.77/0.64). Exact model version to pin: jev-1.13.0. Latency 0.7-1.1s per field request; ~450-650 in / 64-133 out tokens.

Phase 1 — Observability (DB-only, zero extra LLM tokens, nothing is ever deleted):

- new tables bot_traces + bot_trace_events (idempotent DDL in db_init.py; ORM in models.py)

- new app/observability.py: _jsonable (UUID/datetime/Decimal/set/enum/dataclass-safe), trace_start, event, log_resolution, link_draft, latest_trace_for_draft, set_trace_status, span() context manager, save_voice (Path.mkdir parents+exist_ok, day folders)

- capture points wired: input.text; input.voice (+voice persisted under OBS_VOICE_DIR); stt.run + per-provider stt.result (success AND failure, latency, model); nlu.request + nlu.result with prompt_hash/prompt_version; entities.extracted; routing.decision (difflib baseline for the phase-6 A/B); ambiguity.sent; ambiguity.user_choice (buttons + free-text reply path); user_choice.pick; draft.render; draft.edit (wizard-side edits detected by the sync loop); draft.commit (quote/supplier/material/project + trace status/quote id); draft.cancel

- compose: persistent ./bot/data:/srv/bot/data volume; bot/.gitignore: data/ (runtime data never committed, never deleted)

- tests: bot/tools/test_observability.py -> 8/8 pass (jsonable cases, trace lifecycle, JSONB round-trip, draft linking, status update, save_voice day-folder mkdir, span task). Verified live: voice file lands on the host volume and is gitignored; rows + files persist across bot restart.

bot/app/db_init.py

@@ -64,6 +64,40 @@ DDL = [
         updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
     )
     """,
+    # ---- Observability (phase 1) — silent pipeline recorder, DB-only -------
+    """
+    CREATE TABLE IF NOT EXISTS bot_traces (
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        chat_id BIGINT NOT NULL,
+        message_id BIGINT,
+        kind VARCHAR(8) NOT NULL,
+        source VARCHAR(16),
+        draft_id UUID,
+        draft_kind VARCHAR(16),
+        committed_quote_id UUID,
+        status VARCHAR(16) NOT NULL DEFAULT 'open',
+        created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+        updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+    )
+    """,
+    "CREATE INDEX IF NOT EXISTS ix_bot_traces_chat ON bot_traces (chat_id, created_at)",
+    "CREATE INDEX IF NOT EXISTS ix_bot_traces_draft ON bot_traces (draft_id)",
+    """
+    CREATE TABLE IF NOT EXISTS bot_trace_events (
+        id BIGSERIAL PRIMARY KEY,
+        trace_id UUID NOT NULL REFERENCES bot_traces(id) ON DELETE CASCADE,
+        stage VARCHAR(32) NOT NULL,
+        ok BOOLEAN NOT NULL DEFAULT TRUE,
+        latency_ms INTEGER,
+        model VARCHAR(64),
+        field VARCHAR(32),
+        payload JSONB NOT NULL DEFAULT '{}'::jsonb,
+        created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+    )
+    """,
+    "CREATE INDEX IF NOT EXISTS ix_bot_trace_events_trace ON bot_trace_events (trace_id, created_at)",
+    "CREATE INDEX IF NOT EXISTS ix_bot_trace_events_stage ON bot_trace_events (stage)",
+    "CREATE INDEX IF NOT EXISTS ix_bot_trace_events_payload ON bot_trace_events USING GIN (payload jsonb_path_ops)",
 ]