fix: route GitHub Pages navigation to static RSC files

[owjs3901]

Summary

• preserve the /yeollin-cms project prefix for vinext RSC requests
• rewrite browser RSC fetches from extensionless routes to exported .rsc files
• map the project root to index.rsc and retain cache-busting query parameters
• normalize GitHub Pages' octet-stream MIME response for vinext

Root cause

GitHub Pages serves /yeollin-cms/media?_rsc=... as HTML. The exported RSC payload is /yeollin-cms/media.rsc, so vinext classified the HTML response as invalid and performed a hard navigation.

Verification

• �un run tsc --noEmit in packages/app`n- demo production build: 22 routes prerendered, 0 skipped
• generated client chunk contains the /yeollin-cms prefix, RSC-header detection, and .rsc rewrite
• live endpoint comparison: extensionless route returns ext/html; .rsc route returns the RSC payload