fix(auth): auth deps use their own DB session; smoke suites made dataset-independent

RUNTIME BUG (caught by live smoke tests): the global auth dependency
queried the request-scoped session, auto-beginning its transaction — any
endpoint opening 'async with db.begin()' afterwards crashed with
'transaction already begun' (POST /materials 500). get_current_user /
get_actor now resolve in a short-lived session (expire_on_commit=False
keeps the context usable detached); inventory/pm scopes keep passing the
request session explicitly.

Smoke suites rewritten against CURRENT contracts:
- assertions are behavior-based (shapes, envelopes, filters), no magic
  seed counts; dynamic lookups instead of hard-coded names/ids
- rerun-tolerant: tolerate 409-on-create by reusing prior artifacts
- aligned with current rules: revert blocked after inventory receipts
  (v2.6), attachments allowed in every status, termsheets optional at
  quote level
- SMOKE_USER/SMOKE_PASSWORD env for login (default tester/123456)

Verified on a fresh volume: migration + audit_log bootstrap, Casdoor
seed (bcrypt), demo data, and 29+76+61 smoke checks all green.

backend/app/auth.py

@@ -26,7 +26,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.config import settings
-from app.db.engine import get_db
+from app.db.engine import AsyncSessionLocal
 from app.models.procurement import Project, User
 from app.utils.errors import (
     ForbiddenError,
@@ -170,11 +170,16 @@ async def pm_project_ids(db: AsyncSession, user: User) -> list:
     return list(rows)
 
 
-async def get_optional_user(request: Request, db: AsyncSession) -> UserContext | None:
+async def get_optional_user(request: Request, db: AsyncSession | None = None) -> UserContext | None:
     """Resolve the caller from the Casdoor Bearer token, or None when absent.
 
     Raises UnauthorizedError for a present-but-invalid token; callers decide
     their own fallback only for the no-token case (e.g. dev headers).
+
+    IMPORTANT: when ``db`` is omitted (pure auth-dependency usage), a
+    short-lived session of its own is used — querying the REQUEST session
+    here would auto-begin its transaction and break endpoints that open
+    explicit ``async with db.begin()`` blocks afterwards.
     """
     auth = request.headers.get("authorization", "")
     if not auth.lower().startswith("bearer "):
@@ -182,13 +187,22 @@ async def get_optional_user(request: Request, db: AsyncSession) -> UserContext |
     token = auth.split(" ", 1)[1].strip()
     if not token:
         return None
+    if db is None:
+        async with AsyncSessionLocal() as own_session:
+            claims = await _verify_token(token)
+            return await context_from_claims(claims, own_session)
     claims = await _verify_token(token)
     return await context_from_claims(claims, db)
 
 
-async def get_current_user(request: Request, db: AsyncSession = Depends(get_db)) -> UserContext:
-    """Require a valid Casdoor token (401 missing/invalid; 403 unprovisioned)."""
-    ctx = await get_optional_user(request, db)
+async def get_current_user(request: Request) -> UserContext:
+    """Require a valid Casdoor token (401 missing/invalid; 403 unprovisioned).
+
+    Resolves the user in its own session (see get_optional_user) so the
+    global auth dependency never interferes with an endpoint's explicit
+    transaction handling.
+    """
+    ctx = await get_optional_user(request)
     if ctx is None:
         raise UnauthorizedError("احراز هویت لازم است — توکن Casdoor ارسال کنید")
     if ctx.role is None:

backend/app/utils/security.py

@@ -5,16 +5,18 @@ a token leak into the database). All routes that use it now sit behind the
 global JWT dependency, so the token is resolved to the authenticated user
 and the display name is recorded instead.
 """
-from fastapi import Depends, Request
-from sqlalchemy.ext.asyncio import AsyncSession
+from fastapi import Request
 
 from app.auth import get_optional_user
-from app.db.engine import get_db
 
 
-async def get_actor(request: Request, db: AsyncSession = Depends(get_db)) -> str | None:
-    """Resolve the caller's display name from the Casdoor Bearer token."""
-    ctx = await get_optional_user(request, db)
+async def get_actor(request: Request) -> str | None:
+    """Resolve the caller's display name from the Casdoor Bearer token.
+
+    Uses its own session (get_optional_user default) — same reason as
+    get_current_user: quote routers open explicit db.begin() blocks.
+    """
+    ctx = await get_optional_user(request)
     if ctx is not None:
         return ctx.display_name
     # Dev-mode header fallback (only active when DEV_LOGIN_ENABLED) carries