feat: TECHNICAL_PLACEHOLDER (NCM 00000000) is replaceable by the product enrichment; real values preserved; Agent 1.3.4

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

central/app/enrichment/resolver.py

@@ -17,6 +17,7 @@ from ..datasets.service import DatasetService
 from ..models import Dataset, NcmEntry
 from . import kb, textnorm
 from .gtin import normalize_gtin
+from .placeholders import is_placeholder, is_writable_empty
 from .quota import ProviderGateway
 
 AUTO, SUGGEST, CONFLICT, INSUFFICIENT, ALREADY, NA = "AUTO_FILL_SAFE", "SUGGESTION_ONLY", "CONFLICT", "INSUFFICIENT_EVIDENCE", "ALREADY_SET", "NOT_APPLICABLE"
@@ -75,7 +76,7 @@ def _field(status, value=None, rule=None, kb_status=None, evidence=None, reason=
 
 
 def _empty(current: dict, name: str) -> bool:
-    return not str(current.get(name) or "").strip()
+    return is_writable_empty(name, current.get(name))
 
 
 def _fiscal_decisions(session, ncm_eval: dict, gtin_kb_verified: bool, current: dict, description: str, *, name_verified=False) -> dict:
@@ -92,7 +93,8 @@ def _fiscal_decisions(session, ncm_eval: dict, gtin_kb_verified: bool, current:
     else:
         out["CLASSIFICACAO_FISCAL"] = _field(INSUFFICIENT, reason="nenhuma fonte com NCM válido no dataset oficial")
     ncm = out["CLASSIFICACAO_FISCAL"]
-    ncm_for_engine = ncm["value"] if ncm["status"] == AUTO else (normalize_code(current.get("CLASSIFICACAO_FISCAL")) or None)
+    own = current.get("CLASSIFICACAO_FISCAL")
+    ncm_for_engine = ncm["value"] if ncm["status"] == AUTO else (None if is_placeholder("CLASSIFICACAO_FISCAL", own) else (normalize_code(own) or None))
     if not ncm_for_engine or (ncm["status"] == ALREADY and not ncm_is_official(session, ncm_for_engine)):
         for name in ("CEST", "IPI"):
             out[name] = _field(ALREADY if not _empty(current, name) else INSUFFICIENT, reason="depende de um NCM oficial válido")