feat(T3): validare completa prezentari + 29 teste

- app/validation.py: reguli de continut (VIN ^[A-HJ-NPR-Z0-9]{17}$ fara O/I/Q,
  nrInm ^[A-Z0-9]{1,10}$, dataPrestatie ∈ [2024-12-01, azi] TZ Bucuresti,
  R-ODO/I-ODO -> odometruInitial obligatoriu, odometruInitial<=odometruFinal,
  odometruFinal numeric, prestatii nevide, b64Image base64 valid)
- erori structurate {field, message} (aceeasi forma ca raspunsul RAR), fara exceptii
- modele Pydantic: normalizare strip/upper pe vin/nrInm/coduri
- router /v1/prezentari: validare inainte de enqueue; esec continut -> needs_data
  (tinut, vizibil in dashboard cu motiv), NU 422; JSON malformat -> 422 (shape)
- tests/: 29 teste (per regula + rutare API + idempotenta)

Verify: pytest 29 passed.

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

app/validation.py

@@ -0,0 +1,136 @@
+"""Validare de domeniu pentru prezentari (T3).
+
+Replica regulile RAR (docs/api-rar-contract.md sect. "Reguli de validare") ÎNAINTE
+de enqueue, ca sa nu primim 4xx de la RAR. Spre deosebire de validarea de SHAPE
+(Pydantic, da 422 la JSON malformat), aceasta e validare de CONTINUT: esecurile NU
+resping cererea, ci marcheaza submission-ul `needs_data` (plan.md sect. 3 — masina de
+stari + failure registry). Asa apar in dashboard cu motiv, corectabile.
+
+Functiile sunt pure (dict -> listă erori), unit-testabile fara DB/HTTP.
+Erorile au forma {field, message} — aceeasi ca raspunsul de eroare RAR.
+"""
+
+from __future__ import annotations
+
+import base64
+import re
+from datetime import date
+from zoneinfo import ZoneInfo
+
+# VIN: 17 caractere, majuscule, fara O/I/Q (plan §2 + contract).
+VIN_RE = re.compile(r"^[A-HJ-NPR-Z0-9]{17}$")
+# Numar inmatriculare: max 10, litere + cifre majuscule.
+NRINM_RE = re.compile(r"^[A-Z0-9]{1,10}$")
+# Coduri care fac odometruInitial obligatoriu.
+ODOMETER_CODES = {"R-ODO", "I-ODO"}
+# Interval dataPrestatie.
+MIN_DATA_PRESTATIE = date(2024, 12, 1)
+TZ_BUCURESTI = ZoneInfo("Europe/Bucharest")
+
+
+def _norm(value: object) -> str:
+    return str(value or "").strip().upper()
+
+
+def _codes(prestatii: list | None) -> list[str]:
+    out: list[str] = []
+    for p in prestatii or []:
+        cod = p.get("cod_prestatie") if isinstance(p, dict) else getattr(p, "cod_prestatie", None)
+        if cod:
+            out.append(str(cod).strip().upper())
+    return out
+
+
+def _parse_int(value: object) -> int | None:
+    s = str(value or "").strip()
+    if s.isdigit():
+        return int(s)
+    return None
+
+
+def today_bucuresti() -> date:
+    from datetime import datetime
+
+    return datetime.now(TZ_BUCURESTI).date()
+
+
+def validate_prezentare(content: dict) -> list[dict]:
+    """Intoarce lista erorilor de continut [{field, message}]. Goala = valid.
+
+    `content` = PrezentareIn.model_dump() (campuri snake_case interne).
+    """
+    errors: list[dict] = []
+
+    # --- VIN ---
+    vin = _norm(content.get("vin"))
+    if not VIN_RE.match(vin):
+        errors.append({
+            "field": "vin",
+            "message": "VIN trebuie sa aiba exact 17 caractere majuscule, fara spatii/caractere speciale si fara O, I, Q.",
+        })
+
+    # --- nrInmatriculare ---
+    nrinm = _norm(content.get("nr_inmatriculare"))
+    if not NRINM_RE.match(nrinm):
+        errors.append({
+            "field": "nr_inmatriculare",
+            "message": "Numarul de inmatriculare trebuie sa aiba max 10 caractere, doar litere si cifre majuscule.",
+        })
+
+    # --- dataPrestatie ∈ [2024-12-01, azi] TZ Bucuresti ---
+    raw_data = str(content.get("data_prestatie") or "").strip()
+    try:
+        d = date.fromisoformat(raw_data)
+    except ValueError:
+        errors.append({"field": "data_prestatie", "message": "Format data invalid; foloseste YYYY-MM-DD."})
+        d = None
+    if d is not None:
+        if d < MIN_DATA_PRESTATIE:
+            errors.append({"field": "data_prestatie", "message": "Data prestatiei nu poate fi anterioara datei de 01.12.2024."})
+        elif d > today_bucuresti():
+            errors.append({"field": "data_prestatie", "message": "Data prestatiei nu poate fi in viitor."})
+
+    # --- odometruFinal (string numeric) ---
+    odo_final = _parse_int(content.get("odometru_final"))
+    if odo_final is None:
+        errors.append({"field": "odometru_final", "message": "odometruFinal trebuie sa fie un numar intreg (ca string)."})
+
+    # --- odometruInitial: obligatoriu daca prestatii ∋ R-ODO/I-ODO; <= odometruFinal ---
+    codes = _codes(content.get("prestatii"))
+    needs_initial = bool(set(codes) & ODOMETER_CODES)
+    raw_initial = content.get("odometru_initial")
+    has_initial = str(raw_initial or "").strip() != ""
+    if needs_initial and not has_initial:
+        errors.append({
+            "field": "odometru_initial",
+            "message": "odometruInitial este obligatoriu cand prestatiile contin R-ODO sau I-ODO.",
+        })
+    if has_initial:
+        odo_initial = _parse_int(raw_initial)
+        if odo_initial is None:
+            errors.append({"field": "odometru_initial", "message": "odometruInitial trebuie sa fie un numar intreg."})
+        elif odo_final is not None and odo_initial > odo_final:
+            errors.append({"field": "odometru_initial", "message": "odometruInitial trebuie sa fie <= odometruFinal."})
+
+    # --- prestatii nevide ---
+    if not codes:
+        errors.append({"field": "prestatii", "message": "Lista de prestatii nu poate fi goala."})
+
+    # --- b64Image: optional, dar daca e prezent trebuie base64 valid ---
+    b64 = content.get("b64_image")
+    if b64:
+        if not _is_valid_base64(str(b64)):
+            errors.append({"field": "b64_image", "message": "b64Image nu este base64 valid."})
+
+    return errors
+
+
+def _is_valid_base64(value: str) -> bool:
+    s = value.strip()
+    if not s:
+        return False
+    try:
+        base64.b64decode(s, validate=True)
+        return True
+    except (ValueError, base64.binascii.Error):  # type: ignore[attr-defined]
+        return False