Switch pnpm->npm to fix esbuild build-script approval (matches astroreal)

- pnpm 11 (brew/corepack) errors 'ERR_PNPM_IGNORED_BUILDS: esbuild ignored'
  even with onlyBuiltDependencies; npm ci handles esbuild cleanly
- Moreminimore-astroreal uses npm ci + npm run build (proven on EasyPanel)
- Add esbuild as direct dep, generate package-lock.json, remove pnpm files
- Dockerfile: npm ci -> npm run build -> node server.js (port 4321)
- Verified: npm ci + npm run build produce dist (40 pages) successfully

package.json

@@ -15,6 +15,7 @@
   },
   "dependencies": {
     "astro": "^7.1.6",
-    "express": "^5.2.1"
+    "express": "^5.2.1",
+    "esbuild": "0.28.1"
   }
 }