refactor: restructure to monorepo architecture

- Move core agent engine to packages/core/
- Add packages/types/ for shared TypeScript types
- Add packages/utils/ for utility functions
- Add apps/cli/ for command-line interface
- Add apps/gateway/ for NestJS WebSocket gateway
- Add apps/server/ for REST API server
- Restructure desktop app (electron/ → src/main/, src/preload/)
- Update pnpm workspace configuration
- Remove legacy src/ directory

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

turbo.json

@@ -1,17 +1,26 @@
 {
   "$schema": "https://turbo.build/schema.json",
-  "globalDependencies": ["src/**"],
+  "globalDependencies": ["tsconfig.json", "tsconfig.base.json"],
   "tasks": {
     "build": {
       "dependsOn": ["^build"],
+      "inputs": ["src/**", "package.json", "tsconfig.json"],
       "outputs": ["dist/**"]
     },
     "dev": {
+      "dependsOn": ["^build"],
       "cache": false,
       "persistent": true
     },
     "typecheck": {
-      "dependsOn": ["^build"]
+      "dependsOn": ["^typecheck"],
+      "inputs": ["src/**", "package.json", "tsconfig.json"],
+      "outputs": []
+    },
+    "lint": {
+      "dependsOn": ["^lint"],
+      "inputs": ["src/**", "package.json"],
+      "outputs": []
     }
   }
 }