feat(web): dashboard ergonomic cu tab-uri, stepper import si microcopy uman (3.4)

Reorganizeaza interfata web pe trei principii, fara a atinge backend-ul de
trimitere (worker, mapping, idempotency, masina de stari neatinse):

- US-001 app/web/labels.py: modul pur stari tehnice -> text uman + clasa CSS
- US-002 bara status /_fragments/status: microcopy uman, defalcare blocate, scoped cont
- US-003 shell 6 tab-uri (Acasa/Import/Coada/Mapari/Cont/Nomenclator): deep-link
  ?tab=, panou activ randat server-side, fragmente inactive lazy, ARIA real
- US-004 stepper import 4 pasi (pur vizual; hx-target + csrf pastrate)
- US-005 Acasa onboarding checklist auto-bifat + colaps + empty states prietenoase

Reparat in cursul VERIFY/CLOSE: izolare teste (reset ratelimit._hits in fixturi),
regresie avertisment "cont in asteptare de activare" (re-introdus in bara status),
culori hardcodate -> variabile paleta. 434 teste pass.

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

app/web/templates/_submissions.html

@@ -18,5 +18,9 @@
 </table>
 </div>
 {% else %}
-<div class="empty">Coada e goala. Trimite o prezentare prin <code>POST /v1/prezentari</code>.</div>
+<div class="empty">
+  Nicio trimitere inca —
+  <a href="/?tab=import">incepe cu Import</a>
+  sau trimite o prezentare prin API.
+</div>
 {% endif %}