refactor: rename package scope from @caldav to @calchat

Rename all workspace packages to reflect the actual project name:
- @caldav/client -> @calchat/client
- @caldav/server -> @calchat/server
- @caldav/shared -> @calchat/shared
- Root package: caldav-mono -> calchat-mono

Update all import statements across client and server to use the new
package names. Update default MongoDB database name and logging service
identifier accordingly.

apps/client/src/stores/AuthStore.ts

@@ -1,6 +1,6 @@
 import { create } from "zustand";
 import { Platform } from "react-native";
-import { User } from "@caldav/shared";
+import { User } from "@calchat/shared";
 import * as SecureStore from "expo-secure-store";
 
 const USER_STORAGE_KEY = "auth_user";

apps/client/src/stores/ChatStore.ts

@@ -1,5 +1,5 @@
 import { create } from "zustand";
-import { ChatMessage, ProposedEventChange } from "@caldav/shared";
+import { ChatMessage, ProposedEventChange } from "@calchat/shared";
 
 type BubbleSide = "left" | "right";
 

apps/client/src/stores/EventsStore.ts

@@ -1,5 +1,5 @@
 import { create } from "zustand";
-import { ExpandedEvent } from "@caldav/shared";
+import { ExpandedEvent } from "@calchat/shared";
 
 interface EventsState {
   events: ExpandedEvent[];