feat(benchmark): smart-routing mode is the point — live results, per-model cost

The benchmark now leads with the product's actual feature. Two explicit modes:

  🧭 Smart routing (default) — every probe goes through cortiq-auto; each row
     shows the router's task label judged against the expected one (✓/✗ with
     "expected: …"), the complexity tier, the chosen model with what that
     request cost, and a task-rule badge when a routing rule fired. KPIs:
     answer quality, classification accuracy, TTFT, tok/s and money spent,
     plus a "requests went to" distribution with per-model cost.
  🎯 Individual models — the old head-to-head comparison, now as the clearly
     separate option (model checkboxes appear only here).

The suite covers all 8 taxonomy labels (added summarization, creative-writing
and chitchat probes; expected labels annotated per test). Results are LIVE:
the table grows a row after every test (with a small fade-in), the progress
card shows the prompt being asked, and a 🏁 verdict toast lands at the end
with the score and the total spend.

12 new strings in all 7 languages.

web/css/styles.css

@@ -586,6 +586,8 @@ body.modal-open { overflow: hidden; }
    room than the search grid before it starts scrolling. */
 .featured-section .hf-grid { max-height: min(62vh, 760px); }
 /* Benchmark view */
+@keyframes bm-in { from { opacity: 0; transform: translateY(-3px); } to { opacity: 1; transform: none; } }
+tbody tr:last-child { animation: bm-in .25s ease; }
 .bm-sum { margin-bottom: 10px; }
 .bm-cell { cursor: pointer; white-space: nowrap; }
 .bm-cell:hover { background: var(--hover); }