feat(ui): #15 U5 — web upload import (HTMX) drop→mapare→preview→confirma

Implementare completa U5 din plan-treapta2.md (sectiunea 13):

- _upload.html: drop zone + buton accesibil (a11y: drag nu e la tastatura),
  drag-and-drop JS, mesaj 'NU se trimite nimic pana confirmi',
  selector foi pt multi-sheet xlsx, stari eroare/mesaj
- _mapcoloane.html: formular mapare coloane cu .maprow/.mapcol.grow,
  sugestii fuzzy pre-selectate, etiichete <label> vizibile, sample values,
  format data configurabil
- _preview_import.html: tabel 6 stari, pills rezumat, filtre pe stare,
  .chk per-rand pe needs_review (D11), banner declarant .banner.warn
  direct deasupra input-ului N (D12), bara confirmare sticky,
  text 'dubla cu randul N' pe duplicate_in_file (D10 daltonism),
  link export CSV randuri esuate
- base.html: .s-needs_review (warn), .s-already_sent/.s-duplicate_in_file
  (muted), .drop-zone, .banner.warn, .sticky-bar, .htmx-indicator
- routes.py: rute /_import/upload/mapare-coloane/preview/reset/confirma;
  helper _web_compute_preview refoloseste _resolve_row_for_preview,
  _already_sent_lookup, _signature din import_router (fara a-l edita);
  commit ON CONFLICT DO NOTHING (TOCTOU); log atestare
- tests/test_import_ui.py: 15 teste (dashboard, upload, mapare, preview,
  confirmare N corect/gresit, reset, erori, multi-sheet, a11y D10/D11/D12)

279 teste total, 0 esecuri.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/web/templates/base.html

@@ -28,8 +28,24 @@
     .pill { font-size:12px; padding:2px 8px; border-radius:99px; border:1px solid var(--line); }
     .s-queued{color:var(--accent);} .s-sending{color:var(--warn);} .s-sent{color:var(--ok);}
     .s-error,.s-needs_data,.s-needs_mapping{color:var(--err);}
+    .s-ok{color:var(--ok);}
+    .s-needs_review{color:var(--warn);}
+    .s-already_sent,.s-duplicate_in_file{color:var(--muted);}
     .muted { color:var(--muted); }
     a { color:var(--accent); }
+    /* Drop zone upload fisier */
+    .drop-zone { border:2px dashed var(--line); border-radius:8px; padding:32px 20px;
+                 text-align:center; transition:border-color .15s,background .15s; }
+    .drop-zone.drag-over { border-color:var(--accent); background:rgba(91,141,239,.05); }
+    /* Banner varianta warn (nu eroare) */
+    .banner.warn { border-left-color:var(--warn); background:#201c0f; }
+    /* Bara confirmare sticky */
+    .sticky-bar { position:sticky; bottom:0; background:var(--card); border-top:1px solid var(--line);
+                  padding:12px 16px; display:flex; align-items:flex-start; gap:16px;
+                  flex-wrap:wrap; z-index:10; }
+    /* Indicator HTMX — ascuns pana la request */
+    .htmx-indicator { display:none; }
+    .htmx-indicator.htmx-request { display:inline; }
     /* Link-uri de actiune in antetul cardurilor: zona de atins mai mare (>=36px) si
        feedback la hover; pe ecrane inguste antetul se rupe curat sub titlu. */
     .cardlink { font-size:13px; padding:7px 10px; border-radius:6px; display:inline-flex;