[codex] Ship desktop runtime in npm package

[rushillshah]

Closes #26

Scope

• include the existing desktop/ runtime in the npm package allowlist
• keep the advertised npm run desktop command usable after installation

Validation

• npm run check passed
• npm pack --dry-run includes all 5 desktop runtime files
• npm test: 65 passed, 4 failed on the known date-sensitive baseline covered by Tests use stale dated fixtures and fail as time advances #23 / PR [codex] Stabilize rolling-window test fixtures #25

Risk

Low. This only adds existing runtime assets to the published tarball; no application behavior changes.

[rushillshah]

Maintenance blocker (2026-07-16): npm run check passes and npm pack --dry-run confirms all five desktop runtime files are shipped. Both CI jobs fail only on the same four date-sensitive baseline tests tracked by #23 and fixed in green draft PR #25 (65 passed / 4 failed here). Next action: review and merge #25, then rerun this PR CI; keep #27 draft until checks pass and review is complete.