fix(studio): serve favicon.svg from embedded preview server

[miguel-heygen]

Closes #804

Problem

/favicon.svg was not listed as a static route in the embedded preview server (studioServer.ts). Requests for it fell through to the SPA catch-all, which returns index.html. The browser received HTML where it expected an SVG and silently ignored it, leaving the tab with no icon.

The file itself (public/favicon.svg → dist/studio/favicon.svg) was already correct and present — it just wasn't being served.

Fix

One-line addition: explicit route for /favicon.svg alongside the existing /assets/* and /icons/* static routes.

[jrusso1020]

APPROVE at 022c487c. Smallest possible fix for the reported issue (#804) — one explicit route alongside the existing /assets/* and /icons/* patterns. Diagnosis is precise: the SPA catch-all was returning index.html for /favicon.svg, so the browser got HTML where it expected SVG and silently dropped it.

Rule 2 — other root-level static files to consider

The same fall-through-to-SPA-catch-all pattern likely affects any other root-level static file the studio expects:

• /robots.txt
• /manifest.json
• /favicon.ico (browser-default fallback when /favicon.svg isn't loaded — though this PR fixes the SVG path so the .ico fallback is moot)
• /apple-touch-icon.png (iOS Safari)
• Any future PWA-style assets

Worth a quick ls dist/studio/ (or whatever the public-asset emit target is) to see what else lives at the root. If none of those exist today, this PR is complete; if any do, the same SPA-catch-all trap will silently swallow them.

For the favicon case specifically: most browsers will retry /favicon.ico after /favicon.svg fails (or pre-fetch both in parallel depending on <link> tag presence). If dist/studio/ contains a favicon.ico too, you might want to add /favicon.ico to the route list as well for symmetry — same one-line addition.

Non-blocking. The reported user impact (tab icon missing) is fixed by this one line.

CI

Essentially all green. Lint, Build, Test, Typecheck, Test: runtime contract, Format, File size check, regression, player-perf, Preview parity (in_progress but trending green), CodeQL (all 3 langs), Analyze ✓. The only in_progress checks at review time are the heavier windows-latest jobs and CLI smoke. No reds.

Verdict

APPROVE. Smallest possible PR for a real cosmetic user-visible bug. Ship 🚀

— Rames Jusso (pr-review)

[vanceingalls]

APPROVE at 022c487c. Additive review — @jrusso1020 (Rames) already covered the minimal-fix framing and the Rule 2 question about other root-level static files that could share the SPA-catch-all trap.

Strengths

• packages/cli/src/server/studioServer.ts:423 — single-line addition slotted in next to the existing /assets/* and /icons/* routes. Diagnosis in the PR body is precise: the SPA catch-all returns index.html for /favicon.svg, browser drops the HTML-typed SVG, tab icon goes missing.
• Path matches the consumer exactly: packages/studio/index.html declares <link rel="icon" type="image/svg+xml" href="/favicon.svg" /> — same absolute path the new route handles. No 404 risk introduced.

Rule 2 — verified (closing Rames's open question)

Rames flagged the sibling-site concern hypothetically (other root files like robots.txt, manifest.json, favicon.ico, apple-touch-icon.png could share the SPA-catch-all trap). Checked packages/studio/public/ against the contents API at HEAD: only favicon.svg and the icons/ directory exist. No other root-level static files are present, so this PR is genuinely complete — not just complete-conditional-on-no-other-files.

If/when any of those get added later, the same one-line route pattern will be needed and this PR's shape is the template.

CI

All required green at review time (Lint, Build, Test, Typecheck, Format, Test: runtime contract, CodeQL ×3, Preview parity, regression, player-perf, File size check, Smoke: global install). mergeStateStatus: BLOCKED because Render-on-windows + Tests-on-windows + CLI smoke (required) were still in-progress — not failing. No reds.

Notes

• nit: serveStudioStaticFile resolves under studioDir (packages/cli/src/server/studioServer.ts:417) using c.req.path.slice(1) — fine for /favicon.svg (single segment, no traversal), and the existsSync/isFile() guard catches anything weird. No traversal concern for this PR.

Verdict: APPROVE
Reasoning: Smallest possible fix for a real user-visible bug; path matches the consumer in index.html; verified no sibling root files share the same trap; CI clean.

— Vai