feat(5.9): US-003 - modal reutilizabil (overlay, focus-trap, a11y) + cleanup inline-expand 5.8

- base.html: #modal-detaliu (role=dialog, aria-modal) + #detaliu-modal-body swap target;
  focus-trap, inert+aria-hidden pe <main>, Esc/backdrop/x inchid, listener trimiteriChanged (R5/R7)
- _coada.html: ancora modal in afara #submissions-wrap; sters #trimitere-detaliu inert vechi
- _submissions.html: randul declanseaza modalul; sters tr.detaliu-rand sibling (R3)
- _trimitere_detaliu.html: script rescris pentru modal, fara marcheazaDetaliuDeschis/scrollIntoView (R4)
- teste: test_web_modal.py nou (3); test_web_detaliu_inline.py sters; test_acasa_trimiteri.py curatat (R3)
- gates: pytest PASS (suita completa 819). Browser E2E + design-review deferate la VERIFY.

Salvat manual: iteratiile Ralph 2-12 au ramas fara turns (30) inainte de commit.

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

tests/test_acasa_trimiteri.py

@@ -68,7 +68,10 @@ def test_acasa_contine_sectiunea_trimiteri(client):
     html = r.text
     assert 'id="filtre-trimiteri"' in html
     assert "/_fragments/submissions" in html
-    assert 'id="trimitere-detaliu"' in html
+    # PRD 5.9 US-003: detaliul s-a mutat in modalul global (#modal-detaliu); vechiul
+    # panou inert #trimitere-detaliu a fost eliminat.
+    assert 'id="modal-detaliu"' in html
+    assert 'id="trimitere-detaliu"' not in html
 
 
 def test_sectiune_trimiteri_are_heading(client):