Copy package.json into Docker runtime image so APP_VERSION reads correctly; v1.1.27

package.json was missing from the runtime stage, causing readPackageVersion()
to throw and fall back to 'unknown'. The git commit hash (from COMMIT_SHA env)
was the only identifier shown.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.1.26",
+  "version": "1.1.27",
   "type": "module",
   "scripts": {
     "dev": "vite",