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/FantasyWatch/Features/Root/RootFeature.swift

@@ -0,0 +1,50 @@
+//
+//  RootFeature.swift
+//  FantasyWatch
+//
+//  Created by Claude Code
+//
+
+import ComposableArchitecture
+import Foundation
+
+@Reducer
+struct RootFeature {
+    @ObservableState
+    struct State: Equatable {
+        var authentication = AuthenticationFeature.State()
+        var matchup: MatchupFeature.State?
+    }
+
+    enum Action {
+        case authentication(AuthenticationFeature.Action)
+        case matchup(MatchupFeature.Action)
+        case handleOAuthCallback(URL)
+    }
+
+    var body: some ReducerOf<Self> {
+        Scope(state: \.authentication, action: \.authentication) {
+            AuthenticationFeature(
+                clientID: ConfigurationManager.yahooClientID,
+                clientSecret: ConfigurationManager.yahooClientSecret
+            )
+        }
+
+        Reduce { state, action in
+            switch action {
+            case .authentication(.yahooTokenResponse(.success)):
+                state.matchup = MatchupFeature.State()
+                return .none
+
+            case .handleOAuthCallback(let url):
+                return .send(.authentication(.yahooOAuthCallback(url)))
+
+            default:
+                return .none
+            }
+        }
+        .ifLet(\.matchup, action: \.matchup) {
+            MatchupFeature()
+        }
+    }
+}