Harden template for production: add comments, fix bugs, add lock file

- Add inline comments to docker-compose.yml explaining the 5 key rules
  (expose vs ports, DB host, DB name persistence, no Traefik labels)
- Add comments to Dockerfile explaining multi-stage build, layer caching,
  and why .dockerignore excludes client/dist
- Add comments to .dockerignore explaining each exclusion
- Fix dev script: use nodemon (auto-restart) instead of node for server.js
- Add postinstall script to auto-install client deps (cd client && npm install)
- Fix SPA fallback: bare return → next() to prevent hanging requests
- Add root package-lock.json for deterministic server dependency installs
- Remove committed tsconfig.tsbuildinfo build artifact, add *.tsbuildinfo to .gitignore
- Update README: simpler install (npm install handles everything), reference SAAC_DEPLOYMENT.md,
  use npx instead of pnpm dlx for shadcn components

README.md

@@ -24,22 +24,23 @@ React + shadcn/ui + Express + PostgreSQL + Redis scaffold for SAAC deployment.
 │   ├── components.json    # shadcn/ui config
 │   ├── vite.config.ts     # Vite config with path aliases
 │   └── package.json       # Client dependencies
-├── docker-compose.yml     # PostgreSQL + Redis + App
+├── docker-compose.yml     # PostgreSQL + Redis + App (see comments inside)
 ├── Dockerfile             # Multi-stage: build React → serve with Express
+├── SAAC_DEPLOYMENT.md     # Deployment rules — READ THIS FIRST
 └── package.json           # Server dependencies
 ```
 
 ## Development
 
 ```bash
-# Install all dependencies
-npm install && cd client && npm install && cd ..
+# Install all dependencies (postinstall auto-installs client deps)
+npm install
 
-# Run backend + frontend concurrently
+# Run backend + frontend concurrently (nodemon + Vite HMR)
 npm run dev
 
 # Or run separately:
-npm run dev:server   # Express on :3000
+npm run dev:server   # Express on :3000 (with nodemon auto-restart)
 npm run dev:client   # Vite on :5173 (proxies /api to :3000)
 ```
 
@@ -47,9 +48,9 @@ npm run dev:client   # Vite on :5173 (proxies /api to :3000)
 
 ```bash
 cd client
-pnpm dlx shadcn@latest add dialog    # Add Dialog component
-pnpm dlx shadcn@latest add table     # Add Table component
-pnpm dlx shadcn@latest add select    # Add Select component
+npx shadcn@latest add dialog    # Add Dialog component
+npx shadcn@latest add table     # Add Table component
+npx shadcn@latest add select    # Add Select component
 ```
 
 Import: `import { Button } from "@/components/ui/button"`
@@ -60,6 +61,8 @@ Import: `import { Button } from "@/components/ui/button"`
 saac deploy
 ```
 
+See `SAAC_DEPLOYMENT.md` for deployment rules, common mistakes, and debugging commands.
+
 ## API Routes
 
 - `GET /health` — Health check (PostgreSQL + Redis)