Add weather feature with WeatherKit integration for mood entries

Fetch and display weather data (temp, condition, hi/lo, humidity) when
users log a mood. Weather is stored as JSON on MoodEntryModel and shown
as a card in EntryDetailView. Premium-gated with location permission
prompt. Includes BGTask retry for failed fetches and full analytics.

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

Shared/BGTask.swift

@@ -10,6 +10,7 @@ import BackgroundTasks
 
 class BGTask {
     static let updateDBMissingID = "com.88oakapps.reflect.dbUpdateMissing"
+    static let weatherRetryID = "com.88oakapps.reflect.weatherRetry"
 
     @MainActor
     class func runFillInMissingDatesTask(task: BGProcessingTask) {
@@ -27,6 +28,33 @@ class BGTask {
         task.setTaskCompleted(success: true)
     }
     
+    @MainActor
+    class func runWeatherRetryTask(task: BGProcessingTask) {
+        BGTask.scheduleWeatherRetry()
+
+        task.expirationHandler = {
+            task.setTaskCompleted(success: false)
+        }
+
+        Task {
+            await WeatherManager.shared.retryPendingWeatherFetches()
+            task.setTaskCompleted(success: true)
+        }
+    }
+
+    class func scheduleWeatherRetry() {
+        let request = BGProcessingTaskRequest(identifier: BGTask.weatherRetryID)
+        request.requiresNetworkConnectivity = true
+        request.requiresExternalPower = false
+        request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)
+
+        do {
+            try BGTaskScheduler.shared.submit(request)
+        } catch {
+            print("Could not schedule weather retry: \(error)")
+        }
+    }
+
     class func scheduleBackgroundProcessing() {
         let request = BGProcessingTaskRequest(identifier: BGTask.updateDBMissingID)
         request.requiresNetworkConnectivity = false