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

packages/shared/.gitignore

@@ -0,0 +1 @@
+dist/

packages/shared/package.json

@@ -2,11 +2,14 @@
   "name": "@calchat/shared",
   "version": "1.0.0",
   "private": true,
-  "main": "./src/index.ts",
-  "types": "./src/index.ts",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
   "exports": {
-    ".": "./src/index.ts",
-    "./*": "./src/*"
+    ".": "./dist/index.js",
+    "./*": "./dist/*"
+  },
+  "scripts": {
+    "build": "tsc"
   },
   "dependencies": {
     "rrule": "^2.8.1"

packages/shared/tsconfig.json

@@ -1,10 +1,10 @@
 {
   "extends": "../../tsconfig.json",
   "compilerOptions": {
-    "composite": true,
     "declaration": true,
-    "declarationMap": true,
-    "module": "ESNext",
+    "outDir": "dist",
+    "rootDir": "src",
+    "module": "CommonJS",
     "target": "ES2020",
     "moduleResolution": "Node",
     "esModuleInterop": true,