Fix API build: shared package emits dist, fix type errors

- packages/shared: tsconfig adds outDir/declaration, package.json adds build script
- apps/api/tsconfig.json: paths now point to shared/dist (.d.ts) instead of source,
  resolves TS6059 rootDir conflict
- apps/api/src/routes/{health,notifications,users}.ts: explicit Router type annotation
  to fix TS2742 portable type inference
- apps/api/src/events/handler.ts: cast via 'as unknown as' to satisfy TS2352
- apps/api/Dockerfile: build shared package before api

apps/api/tsconfig.json

@@ -10,8 +10,8 @@
     "esModuleInterop": true,
     "declaration": true,
     "paths": {
-      "@naturcalabacera/shared": ["../../packages/shared/src/index.ts"],
-      "@naturcalabacera/shared/*": ["../../packages/shared/src/*"]
+      "@naturcalabacera/shared": ["../../packages/shared/dist/index.d.ts"],
+      "@naturcalabacera/shared/*": ["../../packages/shared/dist/*"]
     }
   },
   "include": ["src"],