feat(webv2): advisory for suspicious Wan A14B expert wiring

[lstein]

Summary

Stacked on #134 (PR 8 of the video panel series). Adds a non-blocking advisory in the Video panel's Model Components section when Wan 2.2 A14B expert wiring looks suspicious, per the swapped-experts experiment discussed during smoke testing.

The backend tags single-file/GGUF Wan checkpoints with an expert field (high/low/none) via a filename heuristic, and wan_model_loader already logs at warning severity when explicit wiring disagrees with the tags — explicit wiring stays authoritative, so deliberate cross-wiring (an experiment the maintainer may actually want) still runs. No backend change was needed; this PR brings the same advisory to the panel at selection time instead of enqueue time.

What it does

getWanExpertWiringWarning (pure, in videoPolicies.ts) inspects the main + low-noise slots of a single-file A14B pairing and reports one of four conditions:

• swapped — main is tagged low, low-noise slot is tagged high
• high-as-low — low-noise slot holds a high-tagged file
• low-as-main — main slot holds a low-tagged file
• single-low — a low-tagged main with no low-noise expert wired (mirrors the loader's single-expert warning)

WanExpertWiringNotice renders the matching message beneath the component slots, with a one-click Swap experts action (hidden for single-low, where there is nothing to swap). The swap routes through the canonical model-selection transition (getVideoModelSelectionResult), so accelerator bookkeeping and model-governed defaults stay consistent; because the low-noise slot filter guarantees a same-variant single-file pair, the swap is a pure role exchange.

Untagged files (expert: 'none', common on community finetunes) never trigger the advisory on their own; Diffusers mains, TI2V-5B (no expert pair), and H3 are out of scope by construction.

Deliberately deferred

An enqueue-time toast backstop for graphs built outside the panel (workflow editor) is deferred — the backend log already covers that path, and the panel is where the mis-wiring is actionable.

Review hardening

The pre-push adversarial review found and this PR fixes: (1) swapping while the model catalog was still loading ran the selection transition against an empty catalog and silently stripped the Lightning accelerator — the Swap button now waits for the catalog to be authoritative; (2) a same-tag pair (high+high / low+low) re-warns after any role exchange, so the button now renders only when simulating the exchange actually clears the warning; (3) the message-key map's hyphenated i18n leaves were invisible to the translation-key scan — renamed to camelCase so the scan really guards them.

Testing

• New unit tests for getWanExpertWiringWarning covering all four warning kinds plus the silent cases (correct wiring, untagged pairs, Diffusers, TI2V-5B, H3, null).
• Full webv2 suite: 6362 tests passing (node) plus 793 browser tests; tsc, oxlint, format, and architecture checks clean.
• Adversarial fresh-context review of the diff completed pre-push.

🤖 Generated with Claude Code

https://claude.ai/code/session_01JYSJ8DZR42nUUhZagaga2z