refactor: split backend into standalone server project

Remove embedded frontend and workflow editor assets, add standalone API deployment configuration, and retain the current backend service updates.

.vscode/launch.json

@@ -2,39 +2,17 @@
   "version": "0.2.0",
   "configurations": [
     {
-      "name": "server",
+      "name": "Agent Desk API",
       "type": "go",
       "request": "launch",
       "mode": "auto",
       "program": "${workspaceFolder}/cmd/server/main.go",
       "cwd": "${workspaceFolder}",
-      "buildFlags": "-tags=dev,lancedb",
-      "env": {
-        "CGO_ENABLED": "1",
-        "CGO_CFLAGS": "-I${workspaceFolder}/include",
-        "CGO_LDFLAGS": "${workspaceFolder}/lib/darwin_arm64/liblancedb_go.a -framework Security -framework CoreFoundation"
-      },
+      "buildFlags": "-tags=dev",
       "args": [
         "-config",
         "${workspaceFolder}/config/config.yaml"
       ]
-    },
-    {
-      "name": "web",
-      "type": "node-terminal",
-      "request": "launch",
-      "command": "pnpm dev",
-      "cwd": "${workspaceFolder}/web"
-    }
-  ],
-  "compounds": [
-    {
-      "name": "server + web",
-      "configurations": [
-        "server",
-        "web"
-      ],
-      "stopAll": true
     }
   ]
 }