fix: remove conflicting API rewrite rule in vercel.json

The rewrite rule for /api/* was intercepting requests before
they could reach the serverless functions, causing Vercel to
return 404 HTML pages instead of proxying to Bugzilla.

Changed to use a negative lookahead so only non-API routes
are rewritten to index.html for the SPA.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: msujaws

vercel.json

@@ -2,10 +2,7 @@
   "buildCommand": "npm run build",
   "outputDirectory": "dist",
   "framework": "vite",
-  "rewrites": [
-    { "source": "/api/(.*)", "destination": "/api/$1" },
-    { "source": "/(.*)", "destination": "/index.html" }
-  ],
+  "rewrites": [{ "source": "/((?!api/).*)", "destination": "/index.html" }],
   "headers": [
     {
       "source": "/(.*)",