fix: resolve all linting and TypeScript issues

- Set up comprehensive ESLint configuration with TypeScript support
- Fix React import issues by adding explicit React imports
- Replace 'any' types with proper TypeScript types (unknown, specific interfaces)
- Add proper type definitions for addressLoader function signature
- Make relays parameter optional in addressLoader interface
- Fix TypeScript strict null checks and function call signatures
- Ensure all code passes ESLint with zero warnings
- Verify TypeScript compilation with no errors
- Maintain strict linting rules without reducing code quality

All linting and type checking now passes successfully.

src/types/nostr.d.ts

@@ -1,8 +1,8 @@
 declare global {
   interface Window {
     nostr?: {
-      getPublicKey(): Promise<string>
-      signEvent(event: any): Promise<any>
+  getPublicKey(): Promise<string>
+  signEvent(event: unknown): Promise<unknown>
     }
   }
 }