feat(signup+admin): aliniere formular signup la landing + plan cerut, GDPR, control tier/trial in panou

Signup:
- /signup aliniat ca format la formularul din landing (campuri, etichete,
  placeholder-uri, select plan, checkbox GDPR, buton). Eticheta `name` = "Companie"
  (corecta: backendul salveaza nume de firma), uniform si in landing.
- Consimtamant GDPR validat server-side (functional, nu doar client-side) + salvat
  cu marca temporala (accounts.consent_at).
- Plan ales la signup salvat in accounts.requested_plan (intentie, NU drept): tier
  ramane sursa de adevar pentru gate-ul API; coloana pregateste integrarea platilor.
- landing: valorile `plan` = coduri tier (free/standard/pro/premium), data-plan
  sincronizat pe butoanele de pret; checkbox consimtamant primeste name.

Schema/DB:
- accounts: coloane noi requested_plan + consent_at (cu migrare aditiva in db.py).

Panou admin:
- Coloane noi: Plan curent (plan EFECTIV acum + zile trial ramase) si Plan cerut.
- Buton "Aplica" (POST /admin/set-tier): aloca plan real si INCHEIE trial-ul
  (efect imediat; altfel trial-ul Pro universal de 30z masca alegerea).
- Control "Trial Pro N zile" (POST /admin/set-trial via accounts.set_trial):
  acorda/prelungeste trial fara a schimba tier-ul de baza.

Teste: signup (consent obligatoriu, requested_plan persistat, tier ramane free),
panou admin (set-tier incheie trial, free opreste Pro imediat, set-trial, validari
+ CSRF). Call-site-urile existente POST /signup actualizate cu consent.

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

app/accounts.py

@@ -44,6 +44,8 @@ def create_account(
     cui: str | None = None,
     email: str | None = None,
     active: bool = True,
+    requested_plan: str | None = None,
+    consent_at: str | None = None,
 ) -> int:
     """Insereaza un cont si intoarce id-ul nou (AUTOINCREMENT, deci >=2 — nu atinge default id=1).
 
@@ -51,12 +53,19 @@ def create_account(
     `email` se normalizeaza (trim+lower); sir gol -> ValueError.
     Un CUI deja folosit -> ValueError cu cauza+fix. Unicitatea e impusa de indexul partial
     `ux_accounts_cui` (nu de un check separat), deci e sigura la concurenta.
+
+    `requested_plan`: planul CERUT la signup (separat de `tier`). NU acorda drepturi — `tier`
+    ramane mereu 'free' la creare; planul cerut e doar o intentie pentru integrarea platilor.
+    Valoare invalida (nu e in VALID_TIERS) -> ignorata (stocata NULL), nu arunca.
+    `consent_at`: marca temporala consimtamant Termeni+GDPR (proba); None = fara flux consimtamant.
     """
     name = (name or "").strip()
     if not name:
         raise ValueError("name gol (un cont are nevoie de nume)")
     cui = _norm_cui(cui)
     email = _norm_email(email)
+    # Planul cerut: pastram doar valori valide; orice altceva -> NULL (defensiv).
+    req_plan = requested_plan if requested_plan in VALID_TIERS else None
     try:
         # Trial Pro automat la creare (PRD 5.17 US-001): tier='free' + trial_until=now+30z.
         trial_until = (
@@ -64,10 +73,11 @@ def create_account(
         )
         # Invariant (5.5): active=1 <=> status='active'; cont creat inactiv = 'pending'.
         cur = conn.execute(
-            "INSERT INTO accounts (name, cui, email, active, status, tier, trial_until) "
-            "VALUES (?, ?, ?, ?, ?, ?, ?)",
+            "INSERT INTO accounts (name, cui, email, active, status, tier, trial_until, "
+            "requested_plan, consent_at) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
             (name, cui, email, 1 if active else 0, "active" if active else "pending",
-             "free", trial_until),
+             "free", trial_until, req_plan, consent_at),
         )
     except sqlite3.IntegrityError:
         existing = conn.execute("SELECT id FROM accounts WHERE cui=?", (cui,)).fetchone()
@@ -185,6 +195,38 @@ def set_tier(
         pass
 
 
+def set_trial(conn: sqlite3.Connection, account_id: int, trial_until: str | None) -> None:
+    """Seteaza DOAR `trial_until` (acorda/prelungeste/sterge trial Pro), fara a atinge `tier`.
+
+    Trial Pro activ (trial_until in viitor) ridica planul efectiv la 'pro' (vezi
+    plans.effective_tier), indiferent de tier-ul de baza. Folosit din panoul admin ca sa
+    acorzi un trial fara a schimba tier-ul de baza (post-trial).
+
+    Contul de sistem id=1 e protejat. Cont inexistent -> ValueError.
+    trial_until: string ISO UTC ("YYYY-MM-DD HH:MM:SS") sau None (sterge trial-ul).
+    """
+    row = conn.execute("SELECT 1 FROM accounts WHERE id=?", (account_id,)).fetchone()
+    if not row:
+        raise ValueError(f"cont inexistent: {account_id}")
+    if account_id == _PROTECTED_ACCOUNT_ID:
+        raise ValueError("Contul default (id=1) nu poate primi trial (cont de sistem).")
+    conn.execute(
+        "UPDATE accounts SET trial_until=? WHERE id=?", (trial_until, account_id)
+    )
+    # Audit in app_events (best-effort, fara PII nou — ca set_tier).
+    try:
+        from .observ import log_event
+        log_event(
+            "plan_trial_setat",
+            account_id=account_id,
+            mesaj=f"trial_until -> {trial_until or 'NULL'}",
+            context={"trial_until": trial_until},
+            conn=conn,
+        )
+    except Exception:  # noqa: BLE001 — jurnal best-effort (ca observ.log_event)
+        pass
+
+
 def delete_account(conn: sqlite3.Connection, account_id: int) -> None:
     """Stergere SOFT: randul ramane ca tombstone (status='deleted', scos din liste), DAR datele
     sensibile se purjeaza IMEDIAT (GDPR/L.142): credentialele RAR criptate sterse, cheile API
@@ -208,7 +250,8 @@ def list_accounts(conn: sqlite3.Connection) -> list[dict]:
     """Metadate conturi (FARA `rar_creds_enc`), ordonate dupa id. Exclude conturile 'deleted'
     (stergere soft -> invizibile in panou)."""
     rows = conn.execute(
-        "SELECT id, name, cui, email, active, status, tier, trial_until, created_at FROM accounts "
+        "SELECT id, name, cui, email, active, status, tier, trial_until, "
+        "requested_plan, consent_at, created_at FROM accounts "
         "WHERE status != 'deleted' ORDER BY id"
     ).fetchall()
     return [dict(r) for r in rows]