Fix test infrastructure for Rooms feature and improve testability

- Update Plant test fixtures to use roomID instead of deprecated location
- Add URLDataFetcher protocol to ImageCache for dependency injection
- Update ImageCacheTests to use protocol-based mock instead of URLSession subclass
- Add missing cancelReminders(for:plantID:) method to MockNotificationService
- Add Equatable conformance to ImageCacheError for test assertions

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

PlantGuideTests/Mocks/MockNotificationService.swift

@@ -26,6 +26,7 @@ final actor MockNotificationService: NotificationServiceProtocol {
     private(set) var scheduleReminderCallCount = 0
     private(set) var cancelReminderCallCount = 0
     private(set) var cancelAllRemindersCallCount = 0
+    private(set) var cancelRemindersForTypeCallCount = 0
     private(set) var updateBadgeCountCallCount = 0
     private(set) var getPendingNotificationsCallCount = 0
     private(set) var removeAllDeliveredNotificationsCallCount = 0
@@ -50,6 +51,8 @@ final actor MockNotificationService: NotificationServiceProtocol {
     private(set) var lastScheduledPlantID: UUID?
     private(set) var lastCancelledTaskID: UUID?
     private(set) var lastCancelledAllPlantID: UUID?
+    private(set) var lastCancelledTaskType: CareTaskType?
+    private(set) var lastCancelledTaskTypePlantID: UUID?
     private(set) var lastBadgeCount: Int?
 
     // MARK: - NotificationServiceProtocol
@@ -100,6 +103,20 @@ final actor MockNotificationService: NotificationServiceProtocol {
         }
     }
 
+    func cancelReminders(for taskType: CareTaskType, plantID: UUID) async {
+        cancelRemindersForTypeCallCount += 1
+        lastCancelledTaskType = taskType
+        lastCancelledTaskTypePlantID = plantID
+
+        // Remove all reminders matching this task type and plant
+        let keysToRemove = scheduledReminders.filter {
+            $0.value.plantID == plantID && $0.value.task.type == taskType
+        }.map { $0.key }
+        for key in keysToRemove {
+            scheduledReminders.removeValue(forKey: key)
+        }
+    }
+
     func updateBadgeCount(_ count: Int) async {
         updateBadgeCountCallCount += 1
         lastBadgeCount = count
@@ -125,6 +142,7 @@ final actor MockNotificationService: NotificationServiceProtocol {
         scheduleReminderCallCount = 0
         cancelReminderCallCount = 0
         cancelAllRemindersCallCount = 0
+        cancelRemindersForTypeCallCount = 0
         updateBadgeCountCallCount = 0
         getPendingNotificationsCallCount = 0
         removeAllDeliveredNotificationsCallCount = 0
@@ -139,6 +157,8 @@ final actor MockNotificationService: NotificationServiceProtocol {
         lastScheduledPlantID = nil
         lastCancelledTaskID = nil
         lastCancelledAllPlantID = nil
+        lastCancelledTaskType = nil
+        lastCancelledTaskTypePlantID = nil
         lastBadgeCount = nil
     }