add auto-updater and git workflow enhancements

This change introduces a comprehensive auto-update mechanism for the application and significant improvements to the integrated Git client experience.

Key features include:
- **Automated Release Workflow:** A new Gitea Actions workflow (`app_builder.yaml`) and a Python `cicd_tool` are added to automatically build, sign, and upload release artifacts to S3-compatible storage (MinIO) upon a new release. This also generates the `latest.json` file required by the updater.
- **Tauri Updater Integration:** The `tauri-plugin-updater` is integrated into the application, enabling it to check for and apply updates seamlessly.
- **Robust Git Push Handling:** The application now intelligently handles non-fast-forward push failures by prompting the user to perform a pull/merge operation before re-attempting the push.
- **Enhanced File Comparison:** A new `compare_file_to_parent` command is introduced, allowing detailed file diffs against a commit's direct parent, including the "empty tree" for initial commits.
- **Explorer Panel Improvements:** "Expand All" and "Collapse All" functionality is added to the file explorer for better navigation.

src-tauri/tauri.conf.json

@@ -29,6 +29,20 @@
   "bundle": {
     "active": true,
     "targets": "all",
-    "icon": ["icons/icon.ico"]
+    "icon": ["icons/icon.ico"],
+    "createUpdaterArtifacts": true,
+    "windows": {
+      "nsis": {
+        "installMode": "currentUser"
+      }
+    }
+  },
+  "plugins": {
+    "updater": {
+      "pubkey": "dW50cnVzdGVkIGNvbW1lbnQ6IG1pbmlzaWduIHB1YmxpYyBrZXk6IDdDNEJGRTZERTREOTc5QjkKUldTNWVkbmtiZjVMZk02YzdpenVLOVltREJpRkFrc2F4dUwzaTV5M3pacFRVR0tmd25xSGtjK1MK",
+      "endpoints" : [
+        "https://cdn.cbsk-tech.de/GitLite/latest.json"
+      ]
+    }
   }
 }