refactor: change domain model IDs from UUID to String canonical IDs

This refactor fixes the achievement system by using stable canonical string
IDs (e.g., "stadium_mlb_fenway_park") instead of random UUIDs. This ensures
stadium mappings for achievements are consistent across app launches and
CloudKit sync operations.

Changes:
- Stadium, Team, Game: id property changed from UUID to String
- Trip, TripStop, TripPreferences: updated to use String IDs for games/stadiums
- CKModels: removed UUID parsing, use canonical IDs directly
- AchievementEngine: now matches against canonical stadium IDs
- All test files updated to use String IDs instead of UUID()

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

SportsTimeTests/Progress/AchievementEngineTests.swift

@@ -181,10 +181,10 @@ final class AchievementEngineIntegrationTests: XCTestCase {
     var modelContainer: ModelContainer!
     var modelContext: ModelContext!
 
-    // Test UUIDs for stadiums
-    let fenwayUUID = UUID(uuidString: "11111111-1111-1111-1111-111111111111")!
-    let wrigleyUUID = UUID(uuidString: "22222222-2222-2222-2222-222222222222")!
-    let msgUUID = UUID(uuidString: "33333333-3333-3333-3333-333333333333")!
+    // Canonical IDs for test stadiums
+    let fenwayId = "stadium_mlb_bos"
+    let wrigleyId = "stadium_mlb_chc"
+    let msgId = "stadium_nba_nyk"
 
     override func setUp() async throws {
         try await super.setUp()
@@ -231,8 +231,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
     private func setupTestData() async {
         // Create Fenway Park stadium
         let fenway = CanonicalStadium(
-            canonicalId: "stadium_mlb_bos",
-            uuid: fenwayUUID,
+            canonicalId: fenwayId,
             name: "Fenway Park",
             city: "Boston",
             state: "MA",
@@ -245,8 +244,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Create Wrigley Field stadium
         let wrigley = CanonicalStadium(
-            canonicalId: "stadium_mlb_chc",
-            uuid: wrigleyUUID,
+            canonicalId: wrigleyId,
             name: "Wrigley Field",
             city: "Chicago",
             state: "IL",
@@ -259,8 +257,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Create MSG stadium
         let msg = CanonicalStadium(
-            canonicalId: "stadium_nba_nyk",
-            uuid: msgUUID,
+            canonicalId: msgId,
             name: "Madison Square Garden",
             city: "New York",
             state: "NY",
@@ -317,10 +314,9 @@ final class AchievementEngineIntegrationTests: XCTestCase {
         // Create engine
         let engine = AchievementEngine(modelContext: modelContext, dataProvider: AppDataProvider.shared)
 
-        // Create a visit to Fenway using the actual stadium UUID format
+        // Create a visit to Fenway using the canonical stadium ID
         let visit = StadiumVisit(
-            canonicalStadiumId: fenwayUUID.uuidString,
-            stadiumUUID: fenwayUUID,
+            stadiumId: fenwayId,
             stadiumNameAtVisit: "Fenway Park",
             visitDate: Date(),
             sport: .mlb
@@ -347,8 +343,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
         let engine = AchievementEngine(modelContext: modelContext, dataProvider: AppDataProvider.shared)
 
         let visit = StadiumVisit(
-            canonicalStadiumId: wrigleyUUID.uuidString,
-            stadiumUUID: wrigleyUUID,
+            stadiumId: wrigleyId,
             stadiumNameAtVisit: "Wrigley Field",
             visitDate: Date(),
             sport: .mlb
@@ -386,8 +381,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Add a visit
         let visit = StadiumVisit(
-            canonicalStadiumId: fenwayUUID.uuidString,
-            stadiumUUID: fenwayUUID,
+            stadiumId: fenwayId,
             stadiumNameAtVisit: "Fenway Park",
             visitDate: Date(),
             sport: .mlb
@@ -406,10 +400,9 @@ final class AchievementEngineIntegrationTests: XCTestCase {
         let engine = AchievementEngine(modelContext: modelContext, dataProvider: AppDataProvider.shared)
 
         // Add TD Garden for NHL
-        let tdGardenUUID = UUID()
+        let tdGardenId = "stadium_nhl_bos"
         let tdGarden = CanonicalStadium(
-            canonicalId: "stadium_nhl_bos",
-            uuid: tdGardenUUID,
+            canonicalId: tdGardenId,
             name: "TD Garden",
             city: "Boston",
             state: "MA",
@@ -437,8 +430,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Visit MLB stadium only - not enough
         let mlbVisit = StadiumVisit(
-            canonicalStadiumId: fenwayUUID.uuidString,
-            stadiumUUID: fenwayUUID,
+            stadiumId: fenwayId,
             stadiumNameAtVisit: "Fenway Park",
             visitDate: Date(),
             sport: .mlb
@@ -453,8 +445,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Visit NBA stadium - still not enough
         let nbaVisit = StadiumVisit(
-            canonicalStadiumId: msgUUID.uuidString,
-            stadiumUUID: msgUUID,
+            stadiumId: msgId,
             stadiumNameAtVisit: "MSG",
             visitDate: Date(),
             sport: .nba
@@ -469,8 +460,7 @@ final class AchievementEngineIntegrationTests: XCTestCase {
 
         // Visit NHL stadium - now earned!
         let nhlVisit = StadiumVisit(
-            canonicalStadiumId: tdGardenUUID.uuidString,
-            stadiumUUID: tdGardenUUID,
+            stadiumId: tdGardenId,
             stadiumNameAtVisit: "TD Garden",
             visitDate: Date(),
             sport: .nhl