Add Docker support with CI workflow and runtime configuration

- Added `Dockerfile` to build a Docker image for the JavadocViewerService.
- Implemented a Gitea-based CI workflow (`deploy-image.yml`) to build and push the Docker image.
- Updated `settings.local.json` to expand permissions for the service.
- Included `-DskipTests` to Maven arguments in `JavadocService.java`.

.claude/settings.local.json

@@ -1,7 +1,9 @@
 {
   "permissions": {
     "allow": [
-      "Bash(java -version)"
+      "Bash(java -version)",
+      "WebFetch(domain:github.com)",
+      "Bash(find /Users/thilo/development/java/JavadocViewerService -not -path */target/* -not -path */.mvn/* -not -path */.maven/* -not -path */.git/* -type f -o -type d)"
     ]
   }
 }