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/Networking/YahooAPI/YahooEndpoints.swift

@@ -0,0 +1,33 @@
+//
+//  YahooEndpoints.swift
+//  FantasyWatch
+//
+//  Created by Claude Code
+//
+
+import Foundation
+
+enum YahooEndpoint: Endpoint {
+    case userTeams
+    case matchup(teamKey: String)
+    case roster(teamKey: String)
+
+    var path: String {
+        switch self {
+        case .userTeams:
+            return "/users;use_login=1/games;game_keys=nhl/teams"
+        case .matchup(let teamKey):
+            return "/team/\(teamKey)/matchups"
+        case .roster(let teamKey):
+            return "/team/\(teamKey)/roster"
+        }
+    }
+
+    var method: HTTPMethod {
+        .get
+    }
+
+    var queryParameters: [String: String]? {
+        ["format": "json"]
+    }
+}