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/Models/Local/LocalPoll.swift

@@ -0,0 +1,134 @@
+//
+//  LocalPoll.swift
+//  SportsTime
+//
+//  SwiftData models for local poll persistence
+//
+
+import Foundation
+import SwiftData
+
+// MARK: - Local Trip Poll
+
+@Model
+final class LocalTripPoll {
+    @Attribute(.unique) var id: UUID
+    var title: String
+    var ownerId: String
+    var shareCode: String
+    var tripSnapshotsData: Data  // Encoded [Trip]
+    var tripVersions: [String]
+    var createdAt: Date
+    var modifiedAt: Date
+    var lastSyncedAt: Date?
+
+    @Relationship(deleteRule: .cascade)
+    var votes: [LocalPollVote]?
+
+    init(
+        id: UUID = UUID(),
+        title: String,
+        ownerId: String,
+        shareCode: String,
+        tripSnapshotsData: Data,
+        tripVersions: [String],
+        createdAt: Date = Date(),
+        modifiedAt: Date = Date(),
+        lastSyncedAt: Date? = nil
+    ) {
+        self.id = id
+        self.title = title
+        self.ownerId = ownerId
+        self.shareCode = shareCode
+        self.tripSnapshotsData = tripSnapshotsData
+        self.tripVersions = tripVersions
+        self.createdAt = createdAt
+        self.modifiedAt = modifiedAt
+        self.lastSyncedAt = lastSyncedAt
+    }
+
+    var tripSnapshots: [Trip] {
+        (try? JSONDecoder().decode([Trip].self, from: tripSnapshotsData)) ?? []
+    }
+
+    func toPoll() -> TripPoll {
+        var poll = TripPoll(
+            id: id,
+            title: title,
+            ownerId: ownerId,
+            shareCode: shareCode,
+            tripSnapshots: tripSnapshots,
+            createdAt: createdAt,
+            modifiedAt: modifiedAt
+        )
+        poll.tripVersions = tripVersions
+        return poll
+    }
+
+    static func from(_ poll: TripPoll) -> LocalTripPoll? {
+        guard let tripsData = try? JSONEncoder().encode(poll.tripSnapshots) else { return nil }
+        return LocalTripPoll(
+            id: poll.id,
+            title: poll.title,
+            ownerId: poll.ownerId,
+            shareCode: poll.shareCode,
+            tripSnapshotsData: tripsData,
+            tripVersions: poll.tripVersions,
+            createdAt: poll.createdAt,
+            modifiedAt: poll.modifiedAt
+        )
+    }
+}
+
+// MARK: - Local Poll Vote
+
+@Model
+final class LocalPollVote {
+    @Attribute(.unique) var id: UUID
+    var pollId: UUID
+    var voterId: String
+    var rankings: [Int]
+    var votedAt: Date
+    var modifiedAt: Date
+    var lastSyncedAt: Date?
+
+    init(
+        id: UUID = UUID(),
+        pollId: UUID,
+        voterId: String,
+        rankings: [Int],
+        votedAt: Date = Date(),
+        modifiedAt: Date = Date(),
+        lastSyncedAt: Date? = nil
+    ) {
+        self.id = id
+        self.pollId = pollId
+        self.voterId = voterId
+        self.rankings = rankings
+        self.votedAt = votedAt
+        self.modifiedAt = modifiedAt
+        self.lastSyncedAt = lastSyncedAt
+    }
+
+    func toVote() -> PollVote {
+        PollVote(
+            id: id,
+            pollId: pollId,
+            odg: voterId,
+            rankings: rankings,
+            votedAt: votedAt,
+            modifiedAt: modifiedAt
+        )
+    }
+
+    static func from(_ vote: PollVote) -> LocalPollVote {
+        LocalPollVote(
+            id: vote.id,
+            pollId: vote.pollId,
+            voterId: vote.odg,
+            rankings: vote.rankings,
+            votedAt: vote.votedAt,
+            modifiedAt: vote.modifiedAt
+        )
+    }
+}