feat: initial implementation of AI Commit Ext VS Code extension

- Add VS Code extension with OpenCode AI integration
- Generate Conventional Commit messages via SCM header button
- Include gitService for staged changes detection
- Include opencodeService for CLI invocation
- Add configuration options for model, includeUnstaged, notifications
- Add button disable during generation with progress indicator
- Add sparkle icon for the action button
- Include package.json, tsconfig, and basic project setup

tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "outDir": "./out",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "types": ["node"],
+    "ignoreDeprecations": "6.0"
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "out"]
+}