Add Pixel Canary eval results

[ZYPX]

Adds Pixel Canary (stealth/pixel-canary) through Vercel AI Gateway and OpenCode, with baseline and AGENTS.md experiments, saved results for all 31 current evals, and the regenerated leaderboard export. Registers it as tier 1 without displacing an existing model; other models' exported data is unchanged.

Setup	Passed	Success rate	Mean cost per eval
Baseline	28/31	90.3%	N/A
With AGENTS.md	30/31	96.8%	N/A

Both configurations use four attempts with early exit and a 2,400-second attempt limit. They reuse the existing pinned OpenCode binary with model metadata supplied through extraProviders. Reasoning effort uses the Gateway default; pricing remains unavailable.

Scoring exception: baseline agent-048-prefetch-url-data retains three genuine validation failures and one 900-second AI-judge timeout as an acknowledged failure. The 28/31 score therefore includes an ungraded timeout, rather than four genuine model failures for that eval. The classification and retry provenance record this explicitly; the cancelled regrading attempt is excluded.

The AGENTS.md variant passes refresh-settings and prefetch-url-data, with no regressions. Its only failed eval is uses-nextjs.

Validation:

• pnpm typecheck
• pnpm test:cost — 9 tests passed
• node scripts/check-stale.mjs — Eval cache OK
• pnpm export-results --check
• Verified full coverage, unchanged exports for other models, and no configured credentials in the new result files.