feat(import): T9 canonicalize_row + build_key partajat (idempotency)

- canonicalize_row: VIN upper, odometru strip ".0" (Excel float coercion),
  data strip — INAINTE de validare si cheie (§3.4bis)
- build_key: aplica account_or_default(None->1) inainte de hash (OV-2):
  canal API (None) si canal import (1) produc aceeasi cheie
- build_key_legacy: helper dual-lookup pentru randuri DB vechi (pre-T9)
- router.py: POST /v1/prezentari foloseste build_key(account_id, canonicalize_row(content))
- 14 teste: canonicalizare, cross-canal, dedup float/int odometru, legacy

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/v1/router.py

@@ -22,7 +22,7 @@ from pydantic import BaseModel, Field
 from ...auth import resolve_account_id
 from ...crypto import encrypt_creds
 from ...db import get_connection
-from ...idempotency import idempotency_key
+from ...idempotency import build_key, canonicalize_row, idempotency_key
 from ...mapping import (
     account_or_default,
     load_mapping,
@@ -63,7 +63,17 @@ def create_prezentari(
         mapping = load_mapping(conn, acct)
         for prez in req.prezentari:
             content = prez.model_dump()
-            key = idempotency_key(account_id, content)
+            # T9/OV-2: canonicalize_row inaintea build_key (odometru strip ".0", VIN upper).
+            # build_key aplica account_or_default(account_id) inainte de hash:
+            # None si 1 colapseaza la aceeasi cheie (canal API + canal import).
+            canon = canonicalize_row(content)
+            key = build_key(account_id, canon)
+            # Aplica normalizarea si in content (odometru canonicalizat inainte de validare, §3.4bis)
+            content.update({
+                "vin": canon["vin"],
+                "nr_inmatriculare": canon["nr_inmatriculare"],
+                "odometru_final": canon["odometru_final"],
+            })
             existing = conn.execute(
                 "SELECT id, status, id_prezentare FROM submissions WHERE idempotency_key=?",
                 (key,),