feat(pm): multi-project PMs (1:N) with project switching, scoping validation and org multi-select

Task 1 — PM 1:N + access-loss handling:
- projects.pm_user_id had no UNIQUE constraint (verified live + in schema); added a lookup index via init_db
- auth: UserContext.project_ids = every project of a PM (oldest first); project_id stays the first for compatibility
- GET /users/me/projects — assigned projects of the caller (drives the switcher + revocation validation)
- login / /users/me / /users list now return the full projects array per user
- /inventory/* and /pm/* scopes accept an explicit ?project_id=… and verify the PM manages it (403 otherwise); without the param they fall back to the first project; admin/manager use it as an optional filter
- POST /users/{id}/project is multi-aware: assigns one project (replacing that project's previous PM) and KEEPS the user's other assignments; null clears all
- PATCH /projects/{id} accepts pm_user_id (admin / procurement manager only)
- frontend: auth store holds projects + the active project (persisted via the existing localStorage store); RequirePmProjects re-validates on load, falls back when the active project was revoked, and shows a dedicated no-projects screen with logout (no redirect loop, no re-auth)
- Panels menu: «مدیریت انبار» gets a ChevronDown accordion listing the PM's projects with «✓ فعلی»; selecting one switches only the active project and reloads the section data
- inventory/pm API calls now send the active project_id explicitly

Task 2 — Organization page:
- new searchable ProjectMultiSelect combobox (chips with ×, live Persian filtering via normalize, assigned projects hidden) replaces the single select for PM users
- add = PATCH project pm_user_id=<user>; × = pm_user_id=null; table and project cards sync immediately; RBAC unchanged (role column admin-only, combobox editable for admin + procurement manager)

Verified locally: 17 scripted checks — multi-project assignment without unique conflicts, /users/me/projects, explicit project_id authorization (foreign project 403 on /inventory, /pm/on-the-way, /pm/receipts), PM blocked from pm_user_id changes, legacy assign endpoint keeps other assignments, revocation removes the project from the list, zero-project PM gets an empty list and a guarded inventory endpoint. All test data cleaned up afterwards.

frontend/src/components/AppSwitcherMenu.tsx

@@ -1,9 +1,14 @@
-import { PanelMenu } from "./PanelMenu";
+import { useLocation } from "react-router-dom";
+import { PanelMenu, type MenuItem } from "./PanelMenu";
 import { useLogout } from "../pages/Inventory/panelMenu";
+import { useAuthStore } from "../store/auth";
 
 // منوی همبرگری مشترک بین دو ماژول (پنل انبار / دفتر تدارکات) —
 // دقیقاً مثل منوی دفتر: عنوان «پنل‌ها»، ماژول فعلی با استایل فعال (پر)
 // + «✓ فعلی»، ماژول دیگر به‌عنوان سوییچر، و در پایان جداکننده + خروج.
+// مدیر پروژه (1:N): زیر «مدیریت انبار» یک آکاردئون باز می‌شود که همه‌ی
+// پروژه‌های تخصیص‌یافته را نشان می‌دهد؛ پروژه‌ی فعال با «✓ فعلی» مشخص است و
+// انتخاب هر پروژه فقط «پروژه‌ی فعال» را عوض می‌کند (نشست/توکن دست‌نخورده).
 export function AppSwitcherMenu({
   activeModule,
   canSwitchToProcurement = true,
@@ -12,13 +17,28 @@ export function AppSwitcherMenu({
   canSwitchToProcurement?: boolean; // مدیر پروژه به دفتر تدارکات دسترسی ندارد
 }) {
   const logout = useLogout();
-  const items = [];
+  const { pathname } = useLocation();
+  const user = useAuthStore((s) => s.user);
+  const setActiveProject = useAuthStore((s) => s.setActiveProject);
+  const items: MenuItem[] = [];
+
+  const isPm = user?.role === "pm";
+  const pmProjects = isPm ? user?.projects ?? [] : [];
+  const projectChildren: MenuItem[] | undefined =
+    activeModule === "warehouse" && isPm
+      ? pmProjects.map((p) => ({
+          label: p.name,
+          to: pathname, // همان بخش فعلی؛ فقط پروژه عوض می‌شود
+          active: p.id === user?.project_id,
+          onClick: () => setActiveProject(p.id),
+        }))
+      : undefined;
 
   if (activeModule === "procurement") {
     items.push({ label: "مدیریت انبار", to: "/inventory" });
     items.push({ label: "مدیریت تدارکات", to: "/", active: true });
   } else {
-    items.push({ label: "مدیریت انبار", to: "/inventory", active: true });
+    items.push({ label: "مدیریت انبار", to: "/inventory", active: true, children: projectChildren });
     if (canSwitchToProcurement) {
       items.push({ label: "مدیریت تدارکات", to: "/" });
     }