feat(security): JWT required on every API route, gated dev fallback, role checks

- main.py: global get_current_user dependency on all routers except
  /auth/login and /health; prod fail-fast startup guard rejects wildcard
  CORS, default credentials, DEV_LOGIN_ENABLED
- inventory/pm: X-User-Role header identity fallback now only active when
  PROCUREMENT_DEV_LOGIN_ENABLED=true (was unconditional in production)
- item_decisions writes + attachment deletes: require_role(
  procurement_manager, admin) — require_role was defined but never used
- config.py: ENVIRONMENT flag, comma-separated CORS_ORIGINS, no default
  Casdoor client secret/admin password, DEV_LOGIN_ENABLED=false
- frontend: authenticated file downloads (Bearer + blob) — <a href> links
  cannot send the token; FileList/QuoteDetail/AcceptModal/EditModal/
  PurchaseHistory converted; DEV_LOGIN_ENABLED build arg defaults false
- smoke tests authenticate via POST /auth/login (SMOKE_USER/SMOKE_PASSWORD)
- traefik: security headers, API rate limit, 12MB body cap (prod overlay)
- nginx client_max_body_size aligned to 12MB

backend/tools/smoke_test_misc.py

@@ -19,6 +19,17 @@ def check(name, ok, extra=""):
 
 c = httpx.Client(base_url=BASE, timeout=30)
 
+# ---------- auth: every endpoint now requires a Casdoor JWT ----------
+import os
+
+r = c.post("/auth/login", json={
+    "username": os.environ.get("SMOKE_USER", "tester"),
+    "password": os.environ.get("SMOKE_PASSWORD", "123456"),
+})
+check("POST /auth/login", r.status_code == 200, r.text[:200])
+if r.status_code == 200:
+    c.headers["Authorization"] = f"Bearer {r.json()['data']['access_token']}"
+
 # ---------- units ----------
 r = c.post("/units", json={"code": "test-unit", "name_fa": "واحد تست", "dimension": "count", "si_factor": 1.0})
 check("POST /units", r.status_code == 201 and r.json()["data"]["id"] > 19, r.text[:200])