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

client/package-lock.json

@@ -2109,6 +2109,66 @@
         "node": ">=14.0.0"
       }
     },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/@emnapi/core": {
+      "version": "1.7.1",
+      "dev": true,
+      "inBundle": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "@emnapi/wasi-threads": "1.1.0",
+        "tslib": "^2.4.0"
+      }
+    },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/@emnapi/runtime": {
+      "version": "1.7.1",
+      "dev": true,
+      "inBundle": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "tslib": "^2.4.0"
+      }
+    },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/@emnapi/wasi-threads": {
+      "version": "1.1.0",
+      "dev": true,
+      "inBundle": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "tslib": "^2.4.0"
+      }
+    },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/@napi-rs/wasm-runtime": {
+      "version": "1.1.0",
+      "dev": true,
+      "inBundle": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "@emnapi/core": "^1.7.1",
+        "@emnapi/runtime": "^1.7.1",
+        "@tybys/wasm-util": "^0.10.1"
+      }
+    },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/@tybys/wasm-util": {
+      "version": "0.10.1",
+      "dev": true,
+      "inBundle": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "tslib": "^2.4.0"
+      }
+    },
+    "node_modules/@tailwindcss/oxide-wasm32-wasi/node_modules/tslib": {
+      "version": "2.8.1",
+      "dev": true,
+      "inBundle": true,
+      "license": "0BSD",
+      "optional": true
+    },
     "node_modules/@tailwindcss/oxide-win32-arm64-msvc": {
       "version": "4.1.18",
       "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-win32-arm64-msvc/-/oxide-win32-arm64-msvc-4.1.18.tgz",