Add API key required overlay and wire up settings state

Remove API key input from repo input component

Add gear icon + settings dialog trigger to header

Add settings dialog component for API key management

Remove server API key fallback — require user-provided key

feat: add BYOK support and migrate from Cloudflare to Vercel

fix: remove postbuild script (timing is wrong, runs before OpenNext creates worker)

fix: rename worker.js to _worker.js for Cloudflare Pages advanced mode

fix: rewrite wrangler.toml for Cloudflare Pages deployment

Add pages_build_output_dir for Cloudflare Pages deployment

feat: add edge runtime exports to all API routes

fix: set KV namespace ID in wrangler.toml

Configure repomind for Cloudflare Pages deployment

Fix TypeScript build error for Cloudflare Pages deployment

Fix critical bugs and prepare for public release