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/web/templates/_mapari.html

@@ -54,11 +54,22 @@
             <div class="muted">{{ e.denumire or '(fara denumire)' }}</div>
           </td>
           <td class="muted" style="font-size:12px;" data-eticheta="Sugestii">
+            {# 5.18 US-007: badge sursa pe sugestia sistemului — confirmat (GOLD) / similar
+               (SILVER+embedding k-NN) / non-operatie (pre-filtru NUL). Suggestion-only. #}
+            {% if e.sugestie_principala %}
+              {% if e.sugestie_principala.sursa == 'gold_partajat' %}
+                <span class="sugg-sursa sugg-sursa--confirmat" title="cod confirmat de un operator">confirmat</span>
+              {% else %}
+                <span class="sugg-sursa sugg-sursa--similar" title="operatie similara deja vazuta (k-NN/exact)">similar</span>
+              {% endif %}
+            {% elif e.surse_sugestie and e.surse_sugestie.nul %}
+              <span class="sugg-sursa sugg-sursa--nul" title="pare non-operatie (ITP/plata/discount...)">non-operatie</span>
+            {% endif %}
             {% if e.suggestions %}
               {% for s in e.suggestions[:3] %}
                 <span class="sugg">{{ s.cod_prestatie }} ({{ s.score|round|int }}%)</span>{% if not loop.last %}, {% endif %}
               {% endfor %}
-            {% else %}—{% endif %}
+            {% elif not e.sugestie_principala and not (e.surse_sugestie and e.surse_sugestie.nul) %}—{% endif %}
           </td>
           <td data-eticheta="Cod RAR">
             <select name="cod_prestatie" form="map-rez-{{ loop.index }}" required