feat(5.18): VERIFY+CLOSE — US-007 badge sursa + fix findings code-review

VERIFY PASS pe corpus k-NN exemple etichetate (seed real 17181 Haiku, comis
in 756f777): suita 1392 passed, 1 deselected (live); smoke init_db seeder
(17181/NUL=2200/idempotent); toate codurile in nomenclator.

US-007 (cerere user la CLOSE) — badge sursa pe sugestia fuzzy din editor:
- _mapari.html: chip confirmat (GOLD) / similar (SILVER+k-NN) / non-operatie (NUL)
- base.html: .sugg-sursa--{confirmat,similar,nul} pe tokeni de tema (color-mix)
- routes.py: cheia `nul` adaugata in surse_sugestie default (finding cross-file)
- tests/test_web_badge_sursa.py: gold/silver/nul/fara-sursa (4 teste)
- E2E render live verificat in serverul real (/_fragments/mapari)

CLOSE /code-review high (main..HEAD, 3 finder x 8 unghiuri) — runtime curat,
invariant #13 intact; 3 findings low/cosmetic REPARATE + lock-uite:
- shared_store.seed_suggestions: cod whitespace -> NULL (era ''), + test lock
- genereaza_seed.py: with open(...) in loc de open().read() (FD leak tool offline)
- embeddings.py: docstring-uri aliniate la [{cod, is_nul, similaritate}]

ROADMAP: 5.18 LIVRAT. PRD: raport VERIFY/CLOSE scris.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/shared_store.py

@@ -46,9 +46,12 @@ def seed_suggestions(
             continue
         is_nul = 1 if item.get("is_nul") else 0
         # NUL -> cod NULL obligatoriu (supresie stricta, #4)
-        cod = None if is_nul else ((item.get("cod_prestatie") or "") or None)
-        if cod:
-            cod = cod.strip().upper()
+        # Normalizeaza INAINTE de truthiness: un cod whitespace-only ("   ") sau
+        # ne-string trebuie sa devina NULL, nu '' (altfel rand non-NUL cu cod gol).
+        cod = None
+        if not is_nul:
+            raw_cod = str(item.get("cod_prestatie") or "").strip().upper()
+            cod = raw_cod or None
         source = str(item.get("source") or "llm")
         confidence = float(item.get("confidence") or 0.0)
         cur = conn.execute(