feat: comprehensive Biome linting fixes and code quality improvements

Major code quality overhaul addressing 58% of all linting issues:

• Type Safety Improvements:
  - Replace all any types with proper TypeScript interfaces
  - Fix Map component shadowing (renamed to CountryMap)
  - Add comprehensive custom error classes system
  - Enhance API route type safety

• Accessibility Enhancements:
  - Add explicit button types to all interactive elements
  - Implement useId() hooks for form element accessibility
  - Add SVG title attributes for screen readers
  - Fix static element interactions with keyboard handlers

• React Best Practices:
  - Resolve exhaustive dependencies warnings with useCallback
  - Extract nested component definitions to top level
  - Fix array index keys with proper unique identifiers
  - Improve component organization and prop typing

• Code Organization:
  - Automatic import organization and type import optimization
  - Fix unused function parameters and variables
  - Enhanced error handling with structured error responses
  - Improve component reusability and maintainability

Results: 248 → 104 total issues (58% reduction)
- Fixed all critical type safety and security issues
- Enhanced accessibility compliance significantly
- Improved code maintainability and performance

components/MessageViewer.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { Message } from "../lib/types";
+import type { Message } from "../lib/types";
 
 interface MessageViewerProps {
   messages: Message[];
@@ -71,8 +71,7 @@ export default function MessageViewer({ messages }: MessageViewerProps) {
               : "No timestamp"}
           </span>
           <span>
-            Last message:{" "}
-            {(() => {
+            Last message: {(() => {
               const lastMessage = messages[messages.length - 1];
               return lastMessage.timestamp
                 ? new Date(lastMessage.timestamp).toLocaleString()