Add contributing workflow and expand gitignore

.gitignore

@@ -1,17 +1,38 @@
+# Dependencies
 node_modules/
 .pnpm-store/
-.next/
+
+# Build output
 dist/
 build/
+.next/
+out/
+*.tsbuildinfo
+
+# Test output
 coverage/
+.nyc_output/
+
+# Runtime and temp files
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+.tmp/
+tmp/
+temp/
+
+# Environment files
 .env
 .env.local
 .env.*.local
-*.log
+
+# IDE and OS files
 .DS_Store
 .vscode/
 .idea/
-.tmp/
-tmp/
+
+# Local databases
 packages/db/prisma/dev.db
 packages/db/prisma/dev.db-journal