feat(errors): erori pe 3 niveluri (problema+cauza+fix) pe API si UI (PRD 5.4)

Catalog central pur app/errors.py ca sursa unica cod->{problema,fix},
consumat de API+UI+worker. Aditiv (field/message pastrate la octet) +
rar_error stocat superset. Scope: fluxul de declarare; login/signup/CSRF
neatinse. labels.parse_erori degradeaza gratios; UI progresiv AA light+dark.
631 teste.

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

app/mapping.py

@@ -20,6 +20,7 @@ from typing import Any
 
 from rapidfuzz import fuzz, process
 
+from . import errors as err_mod
 from .nomenclator_seed import FALLBACK_NOMENCLATOR
 from .validation import validate_prezentare
 
@@ -245,7 +246,11 @@ def classify_prezentare(
 
     if unmapped:
         status = "needs_mapping"
-        rar_error = json.dumps({"unmapped": unmapped}, ensure_ascii=False)
+        coduri = ", ".join((u.get("cod_op_service") or "") for u in unmapped)
+        rar_error = json.dumps(
+            {"unmapped": unmapped, **err_mod.eroare("COD_NEMAPAT", cauza=f"Coduri fara mapare RAR: {coduri}")},
+            ensure_ascii=False,
+        )
         errors: list[dict] = []
     else:
         errors = validate_prezentare(c)
@@ -254,8 +259,9 @@ def classify_prezentare(
             rar_error = json.dumps(errors, ensure_ascii=False)
         elif has_no_auto_send(resolved, mapping_meta):
             status = "needs_mapping"
+            mesaj = "cod mapat cu auto_send=0; review manual inainte de trimitere"
             rar_error = json.dumps(
-                {"auto_send": "cod mapat cu auto_send=0; review manual inainte de trimitere"},
+                {"auto_send": mesaj, **err_mod.eroare("AUTO_SEND_OPRIT", cauza=mesaj)},
                 ensure_ascii=False,
             )
         else: