feat(5.20): US-004/005/006/009 ingestie+API+worker+import pe mediu RAR

US-004: rezolva_rar_env (cerere>default cont>ancora globala) + MediuIndisponibil
+ cod RAR_MEDIU_INDISPONIBIL.
US-005: camp rar_env pe POST /v1/prezentari + /valideaza (Literal), echo in
SubmissionResult/ValidareResult/GET, build_key + INSERT env-aware.
US-006: AccountSessions re-cheiat (account_id, rar_env); RarClient base_url per
env; creds din slotul env; purge + recover_orphans scoped pe env (E1/1a, 1b/E6);
claim_one propaga rar_env (1c/E8); keepalive pe ancora globala (M2).
US-009: selector mediu la import (>=2 medii), eticheta la 1, banner la 0; commit
seteaza rar_env pe submissions.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_creds_delivery.py

@@ -157,7 +157,7 @@ class FakeRarClient:
 
     made: list = []
 
-    def __init__(self, settings=None, login_exc=None):
+    def __init__(self, settings=None, *, base_url=None, login_exc=None):
         self.closed = False
         self.login_calls = 0
         self._login_exc = login_exc
@@ -234,7 +234,7 @@ def test_get_token_bad_creds_raises(env, monkeypatch):
     import app.worker.__main__ as w
     from app.db import get_connection
 
-    def _factory(settings=None):
+    def _factory(settings=None, **kwargs):
         return FakeRarClient(settings, login_exc=RarAuthError("Credentiale RAR invalide", status_code=401))
 
     monkeypatch.setattr(w, "RarClient", _factory)