Phase 1: Replace Privy auth with native Farcaster Mini App authentication

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Overview

Replace the current Privy authentication system with native Farcaster Mini App authentication to make SoundProof truly Farcaster-native.

Tasks

• Remove Privy dependencies from package.json
• Implement Farcaster Mini App SDK authentication
• Update AuthContext to use Farcaster user data instead of Privy
• Replace wallet connection flow with Farcaster's built-in wallet integration
• Update all authentication checks throughout the app
• Test authentication flow in Farcaster Mini App environment

Acceptance Criteria

• Users can authenticate using "Sign in with Farcaster" without Privy
• User profile data comes from Farcaster account
• Wallet connection works through Farcaster Mini App SDK
• All existing authentication-dependent features continue to work
• App loads and functions properly within Farcaster clients

Priority

High - Foundation for all other Farcaster integration work

Dependencies

• Farcaster Mini App SDK (already installed)
• Farcaster manifest (already created)