fix: resolve all Biome linting errors and Prettier formatting issues

- Reduce cognitive complexity in lib/api/handler.ts (23 → 15)
- Reduce cognitive complexity in lib/config/provider.ts (38 → 15)
- Fix TypeScript any type violations in multiple files
- Remove unused variable in lib/batchSchedulerOptimized.ts
- Add prettier-ignore comments to documentation with intentional syntax errors
- Resolve Prettier/Biome formatting conflicts with targeted ignores
- Create .prettierignore for build artifacts and dependencies

All linting checks now pass and build completes successfully (47/47 pages).

components/MessageViewer.tsx

@@ -70,6 +70,7 @@ export default function MessageViewer({ messages }: MessageViewerProps) {
               ? new Date(messages[0].timestamp).toLocaleString()
               : "No timestamp"}
           </span>
+          {/* prettier-ignore */}
           <span>
             Last message: {(() => {
               const lastMessage = messages[messages.length - 1];