feat(benchmark): the built-in benchmark, redesigned into the console

The old standalone benchmark.html (Russian-only, Tailwind+Chart.js from CDNs,
never shipped in the crate) becomes a proper sidebar view. Same scoring ideas,
reimplemented: keyword checks with |-synonyms, think-tag stripping, tail-loop
detection, pass/partial/fail — plus what the old page never had: runs go
through the LIVE pipeline (pinned per model, streamed), so every test also
measures tok/s and time-to-first-token with the gateway's real token counts.

A built-in suite of 12 language-neutral probes (math, logic, code, QA,
instruction-following, extraction, translation, JSON formatting); the ⚡ quick
mode runs the 6 short ones — about a minute on a local model. Results: score
bars per model sorted best-first, a per-test grid (click a cell for the full
answer), previous runs and custom tests kept in the browser.

22 new strings in all 7 languages.

web/css/styles.css

@@ -585,6 +585,12 @@ body.modal-open { overflow: hidden; }
 /* Featured gallery: the list grows as new models are published, so give it more
    room than the search grid before it starts scrolling. */
 .featured-section .hf-grid { max-height: min(62vh, 760px); }
+/* Benchmark view */
+.bm-sum { margin-bottom: 10px; }
+.bm-cell { cursor: pointer; white-space: nowrap; }
+.bm-cell:hover { background: var(--hover); }
+.badge.ok { background: rgba(52,211,153,.15); color: var(--good); }
+
 /* Routing: per-task rule rows */
 .taskrow { align-items: flex-start; }
 .taskname { min-width: 190px; line-height: 1.35; }