feat: add CalDAV synchronization with automatic sync

- Add CaldavService with tsdav/ical.js for CalDAV server communication
- Add CaldavController, CaldavRepository, and caldav routes
- Add client-side CaldavConfigService with sync(), config CRUD
- Add CalDAV settings UI with config load/save in settings screen
- Sync on login, auto-login (AuthGuard), periodic timer (calendar), and sync button
- Push single events to CalDAV on server-side create/update/delete
- Push all events to CalDAV after chat event confirmation
- Refactor ChatService to use EventService instead of direct EventRepository
- Rename CalDav/calDav to Caldav/caldav for consistent naming
- Add Radicale Docker setup for local CalDAV testing
- Update PlantUML diagrams and CLAUDE.md with CalDAV architecture

docs/frontend-class-diagram.puml

@@ -22,18 +22,26 @@ package "Screens" #87CEEB {
     class RegisterScreen
     class CalendarScreen
     class ChatScreen
+    class SettingsScreen
+    class EditEventScreen
     class EventDetailScreen
     class NoteScreen
 }
 
 ' ===== COMPONENTS =====
 package "Components" #FFA07A  {
+    class AuthGuard
     class BaseBackground
     class Header
+    class BaseButton
+    class CardBase
+    class ModalBase
     class EventCardBase
     class EventCard
     class ProposedEventCard
-    class EventConfirmDialog
+    class DeleteEventModal
+    class ChatBubble
+    class TypingIndicator
 }
 
 ' ===== SERVICES =====
@@ -64,6 +72,13 @@ package "Services" #90EE90 {
         +rejectEvent()
         +getConversations()
         +getConversation()
+        +updateProposalEvent()
+    }
+    class CaldavConfigService {
+        +getConfig()
+        +saveConfig()
+        +deleteConfig()
+        +sync()
     }
 }
 
@@ -71,11 +86,10 @@ package "Services" #90EE90 {
 package "Stores" #FFD700 {
     class AuthStore {
         ' +user
-        ' +token
         ' +isAuthenticated
         ' +login()
         ' +logout()
-        ' +setToken()
+        ' +loadStoredUser()
     }
     class EventsStore {
         ' +events
@@ -86,10 +100,16 @@ package "Stores" #FFD700 {
     }
     class ChatStore {
         ' +messages
+        ' +isWaitingForResponse
         ' +addMessage()
+        ' +addMessages()
         ' +updateMessage()
         ' +clearMessages()
     }
+    class ThemeStore {
+        ' +theme
+        ' +setTheme()
+    }
 }
 
 ' ===== MODELS =====
@@ -97,6 +117,7 @@ package "Models (shared)" #D3D3D3 {
     class User
     class CalendarEvent
     class ChatMessage
+    class CaldavConfig
 }
 
 ' ===== RELATIONSHIPS =====
@@ -104,24 +125,39 @@ package "Models (shared)" #D3D3D3 {
 ' Screens -> Services
 LoginScreen --> AuthService
 CalendarScreen --> EventService
+CalendarScreen --> CaldavConfigService
 ChatScreen --> ChatService
 NoteScreen --> EventService
+EditEventScreen --> EventService
+EditEventScreen --> ChatService
+SettingsScreen --> CaldavConfigService
 
 ' Screens -> Components
 CalendarScreen --> EventCard
 ChatScreen --> ProposedEventCard
-ChatScreen --> EventConfirmDialog
+ChatScreen --> ChatBubble
+ChatScreen --> TypingIndicator
 EventCard --> EventCardBase
 ProposedEventCard --> EventCardBase
+EventCardBase --> CardBase
+ModalBase --> CardBase
+DeleteEventModal --> ModalBase
+
+' Auth
+AuthGuard --> AuthStore
+AuthGuard --> CaldavConfigService
+LoginScreen --> CaldavConfigService
 
 ' Services -> ApiClient
 AuthService --> ApiClient
 EventService --> ApiClient
 ChatService --> ApiClient
+CaldavConfigService --> ApiClient
 
 ' Services/Screens -> Stores
 AuthService --> AuthStore
-EventService --> EventsStore
+CalendarScreen --> EventsStore
 ChatScreen --> ChatStore
+SettingsScreen --> ThemeStore
 
 @enduml