Initial implementation of Fantasy Hockey watchOS app

Implemented complete TCA architecture for iOS and watchOS targets:
- Authentication flow (Sign in with Apple + Yahoo OAuth)
- OAuth token management with iCloud Key-Value Storage
- Yahoo Fantasy Sports API client with async/await
- Watch Connectivity for iPhone ↔ Watch data sync
- Complete UI for both iPhone and Watch platforms

Core features:
- Matchup score display
- Category breakdown with win/loss/tie indicators
- Roster status tracking
- Manual refresh functionality
- Persistent data caching on Watch

Technical stack:
- The Composable Architecture for state management
- Swift Concurrency (async/await, actors)
- WatchConnectivity framework
- Sign in with Apple
- OAuth 2.0 authentication flow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

FantasyWatch/Shared/WatchConnectivity/MessageTypes.swift

@@ -0,0 +1,20 @@
+//
+//  MessageTypes.swift
+//  FantasyWatch
+//
+//  Created by Claude Code
+//
+
+import Foundation
+
+enum WatchMessage: String, Codable {
+    case matchupUpdate
+    case refreshRequest
+    case authenticationRequired
+}
+
+struct WatchPayload: Codable, Sendable {
+    let matchup: Matchup
+    let roster: RosterStatus
+    let timestamp: Date
+}