Add Plant Rooms/Zones feature for organizing plants by location

Implements Phase 3 of the feature roadmap:
- Room entity with 7 default rooms (Kitchen, Living Room, Bedroom, etc.)
- RoomRepositoryProtocol and CoreDataRoomRepository for persistence
- CreateDefaultRoomsUseCase and ManageRoomsUseCase for CRUD operations
- RoomsListView with swipe-to-delete and drag-to-reorder
- RoomEditorView with SF Symbol icon picker
- RoomPickerView for assigning plants to rooms
- Updated Plant entity (location → roomID) and PlantDetailView
- Added "Manage Rooms" section in SettingsView

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

PlantGuide/Presentation/Scenes/PlantDetail/PlantDetailView.swift

@@ -45,6 +45,9 @@ struct PlantDetailView: View {
                 } else if let error = viewModel.error {
                     errorView(error: error)
                 } else {
+                    // Room assignment section
+                    roomSection
+
                     // Care information section
                     if let careInfo = viewModel.careInfo {
                         CareInformationSection(careInfo: careInfo)
@@ -293,6 +296,34 @@ struct PlantDetailView: View {
         }
     }
 
+    // MARK: - Room Section
+
+    private var roomSection: some View {
+        VStack(alignment: .leading, spacing: 12) {
+            Text("Location")
+                .font(.headline)
+
+            RoomPickerView(
+                selectedRoomID: Binding(
+                    get: { viewModel.plant.roomID },
+                    set: { newRoomID in
+                        Task {
+                            await viewModel.updateRoom(to: newRoomID)
+                        }
+                    }
+                ),
+                onRoomChanged: { newRoomID in
+                    Task {
+                        await viewModel.updateRoom(to: newRoomID)
+                    }
+                }
+            )
+        }
+        .padding()
+        .background(Color(.systemGray6))
+        .cornerRadius(12)
+    }
+
     // MARK: - Identification Info Section
 
     private var identificationInfoSection: some View {