feat(polls): implement group trip polling MVP

Add complete group trip polling feature allowing users to share trips
with friends for voting using Borda count scoring.

New components:
- TripPoll and PollVote domain models with share codes and rankings
- LocalTripPoll and LocalPollVote SwiftData models for persistence
- CKTripPoll and CKPollVote CloudKit record wrappers
- PollService actor for CloudKit CRUD operations and subscriptions
- PollCreation/Detail/Voting views and view models
- Deep link handling for sportstime://poll/{code} URLs
- Debug Pro status override toggle in Settings

Integration:
- HomeView shows polls section in My Trips
- SportsTimeApp registers SwiftData models and handles deep links

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTime/Core/Store/StoreManager.swift

@@ -31,10 +31,31 @@ final class StoreManager {
     private(set) var isLoading = false
     private(set) var error: StoreError?
 
+    // MARK: - Debug Override (DEBUG builds only)
+
+    #if DEBUG
+    private static let debugProOverrideKey = "debugProOverride"
+
+    /// When true, isPro returns true regardless of actual subscription status.
+    /// Defaults to true in debug builds. Only compiled in DEBUG configuration.
+    var debugProOverride: Bool {
+        get {
+            // Default to true by checking if key exists; object(forKey:) returns nil if not set
+            UserDefaults.standard.object(forKey: Self.debugProOverrideKey) as? Bool ?? true
+        }
+        set {
+            UserDefaults.standard.set(newValue, forKey: Self.debugProOverrideKey)
+        }
+    }
+    #endif
+
     // MARK: - Computed Properties
 
     var isPro: Bool {
-        !purchasedProductIDs.intersection(Self.proProductIDs).isEmpty
+        #if DEBUG
+        if debugProOverride { return true }
+        #endif
+        return !purchasedProductIDs.intersection(Self.proProductIDs).isEmpty
     }
 
     var monthlyProduct: Product? {