fix: 22 audit fixes — concurrency, memory, performance, accessibility

- Move 7 Data(contentsOf:) calls off MainActor via Task.detached (BootstrapService)
- Batch-fetch N+1 queries in sync merge loops (CanonicalSyncService)
- Predicate-based gamesForTeam fetch instead of fetching all games (DataProvider)
- Proper Sendable on RouteInfo with nonisolated(unsafe) polyline (LocationService)
- [weak self] in BGTaskScheduler register closures (BackgroundSyncManager)
- Cache tripDays, routeWaypoints as @State with recompute (TripDetailView)
- Remove unused AnyCancellable, add Task lifecycle management (TripDetailView)
- Cache sportStadiums, recentVisits as stored properties (ProgressViewModel)
- Dynamic Type fonts replacing hardcoded sizes (OnboardingPaywallView)
- Accessibility labels/hints on stadium picker, date picker, map, stats,
  settings toggle, and day cards

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SportsTime/Core/Services/CanonicalSyncService.swift

@@ -429,11 +429,16 @@ final class CanonicalSyncService {
         var skippedIncompatible = 0
         var skippedOlder = 0
 
+        // Batch-fetch all existing stadiums to avoid N+1 FetchDescriptor lookups
+        let allExistingStadiums = try context.fetch(FetchDescriptor<CanonicalStadium>())
+        let existingStadiumsByCanonicalId = Dictionary(grouping: allExistingStadiums, by: \.canonicalId).compactMapValues(\.first)
+
         for syncStadium in syncStadiums {
             // Use canonical ID directly from CloudKit - no UUID-based generation!
             let result = try mergeStadium(
                 syncStadium.stadium,
                 canonicalId: syncStadium.canonicalId,
+                existingRecord: existingStadiumsByCanonicalId[syncStadium.canonicalId],
                 context: context
             )
 
@@ -465,6 +470,10 @@ final class CanonicalSyncService {
         var skippedIncompatible = 0
         var skippedOlder = 0
 
+        // Batch-fetch all existing teams to avoid N+1 FetchDescriptor lookups
+        let allExistingTeams = try context.fetch(FetchDescriptor<CanonicalTeam>())
+        let existingTeamsByCanonicalId = Dictionary(grouping: allExistingTeams, by: \.canonicalId).compactMapValues(\.first)
+
         for syncTeam in allSyncTeams {
             // Use canonical IDs directly from CloudKit - no UUID lookups!
             let result = try mergeTeam(
@@ -472,6 +481,7 @@ final class CanonicalSyncService {
                 canonicalId: syncTeam.canonicalId,
                 stadiumCanonicalId: syncTeam.stadiumCanonicalId,
                 validStadiumIds: &validStadiumIds,
+                existingRecord: existingTeamsByCanonicalId[syncTeam.canonicalId],
                 context: context
             )
 
@@ -514,6 +524,10 @@ final class CanonicalSyncService {
         var skippedIncompatible = 0
         var skippedOlder = 0
 
+        // Batch-fetch all existing games to avoid N+1 FetchDescriptor lookups
+        let allExistingGames = try context.fetch(FetchDescriptor<CanonicalGame>())
+        let existingGamesByCanonicalId = Dictionary(grouping: allExistingGames, by: \.canonicalId).compactMapValues(\.first)
+
         for syncGame in syncGames {
             // Use canonical IDs directly from CloudKit - no UUID lookups!
             let result = try mergeGame(
@@ -525,6 +539,7 @@ final class CanonicalSyncService {
                 validTeamIds: validTeamIds,
                 teamStadiumByTeamId: teamStadiumByTeamId,
                 validStadiumIds: &validStadiumIds,
+                existingRecord: existingGamesByCanonicalId[syncGame.canonicalId],
                 context: context
             )
 
@@ -649,13 +664,19 @@ final class CanonicalSyncService {
     private func mergeStadium(
         _ remote: Stadium,
         canonicalId: String,
+        existingRecord: CanonicalStadium? = nil,
         context: ModelContext
     ) throws -> MergeResult {
-        // Look up existing
-        let descriptor = FetchDescriptor<CanonicalStadium>(
-            predicate: #Predicate { $0.canonicalId == canonicalId }
-        )
-        let existing = try context.fetch(descriptor).first
+        // Use pre-fetched record if available, otherwise fall back to individual fetch
+        let existing: CanonicalStadium?
+        if let existingRecord {
+            existing = existingRecord
+        } else {
+            let descriptor = FetchDescriptor<CanonicalStadium>(
+                predicate: #Predicate { $0.canonicalId == canonicalId }
+            )
+            existing = try context.fetch(descriptor).first
+        }
 
         if let existing = existing {
             // Preserve user fields
@@ -715,12 +736,19 @@ final class CanonicalSyncService {
         canonicalId: String,
         stadiumCanonicalId: String?,
         validStadiumIds: inout Set<String>,
+        existingRecord: CanonicalTeam? = nil,
         context: ModelContext
     ) throws -> MergeResult {
-        let descriptor = FetchDescriptor<CanonicalTeam>(
-            predicate: #Predicate { $0.canonicalId == canonicalId }
-        )
-        let existing = try context.fetch(descriptor).first
+        // Use pre-fetched record if available, otherwise fall back to individual fetch
+        let existing: CanonicalTeam?
+        if let existingRecord {
+            existing = existingRecord
+        } else {
+            let descriptor = FetchDescriptor<CanonicalTeam>(
+                predicate: #Predicate { $0.canonicalId == canonicalId }
+            )
+            existing = try context.fetch(descriptor).first
+        }
 
         let remoteStadiumId = stadiumCanonicalId?.trimmingCharacters(in: .whitespacesAndNewlines)
         let existingStadiumId = existing?.stadiumCanonicalId.trimmingCharacters(in: .whitespacesAndNewlines)
@@ -809,12 +837,19 @@ final class CanonicalSyncService {
         validTeamIds: Set<String>,
         teamStadiumByTeamId: [String: String],
         validStadiumIds: inout Set<String>,
+        existingRecord: CanonicalGame? = nil,
         context: ModelContext
     ) throws -> MergeResult {
-        let descriptor = FetchDescriptor<CanonicalGame>(
-            predicate: #Predicate { $0.canonicalId == canonicalId }
-        )
-        let existing = try context.fetch(descriptor).first
+        // Use pre-fetched record if available, otherwise fall back to individual fetch
+        let existing: CanonicalGame?
+        if let existingRecord {
+            existing = existingRecord
+        } else {
+            let descriptor = FetchDescriptor<CanonicalGame>(
+                predicate: #Predicate { $0.canonicalId == canonicalId }
+            )
+            existing = try context.fetch(descriptor).first
+        }
 
         func resolveTeamId(remote: String, existing: String?) -> String? {
             if validTeamIds.contains(remote) {