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

lib/transcriptFetcher.ts

@@ -30,7 +30,7 @@ export async function fetchTranscriptContent(
     // Prepare authentication header if credentials provided
     const authHeader =
       username && password
-        ? "Basic " + Buffer.from(`${username}:${password}`).toString("base64")
+        ? `Basic ${Buffer.from(`${username}:${password}`).toString("base64")}`
         : undefined;
 
     const headers: Record<string, string> = {
@@ -141,7 +141,7 @@ export function extractSessionIdFromTranscript(content: string): string | null {
 
   for (const pattern of patterns) {
     const match = content.match(pattern);
-    if (match && match[1]) {
+    if (match?.[1]) {
       return match[1].trim();
     }
   }