feat: add Docker support and compile shared package to dist

- Add multi-stage Dockerfile for server containerization
- Add .dockerignore to exclude unnecessary files from build context
- Switch shared package from source to compiled CommonJS output (dist/)
- Server dev/build scripts now build shared package first
- Fix deep imports to use @calchat/shared barrel export
- Update CLAUDE.md with Docker and shared package documentation

apps/server/src/services/CaldavService.ts

@@ -6,9 +6,10 @@ import { CaldavRepository } from "./interfaces/CaldavRepository";
 import {
   CalendarEvent,
   CreateEventDTO,
-} from "@calchat/shared/src/models/CalendarEvent";
+  CaldavConfig,
+  formatDateKey,
+} from "@calchat/shared";
 import { EventService } from "./EventService";
-import { CaldavConfig, formatDateKey } from "@calchat/shared";
 
 const logger = createLogger("CaldavService");
 

apps/server/src/services/interfaces/CaldavRepository.ts

@@ -1,4 +1,4 @@
-import { CaldavConfig } from "@calchat/shared/src/models/CaldavConfig";
+import { CaldavConfig } from "@calchat/shared";
 
 export interface CaldavRepository {
   findByUserId(userId: string): Promise<CaldavConfig | null>;