fix: install Agent-backend deps before orbit-server build in CI

Agent-backend is a separate workspace with its own bun.lock — needs
its own `bun install` before `build:opencode` can resolve @OpenTui.

Author: fazxes

.github/workflows/tauri-build.yml

@@ -82,8 +82,12 @@ jobs:
           chmod +x ../src-tauri/binaries/agent-bridge-aarch64-apple-darwin
 
       # Build orbit-server sidecar (OpenCode engine, Bun standalone binary)
+      # Agent-backend is a separate workspace — install its deps first
       - name: Build orbit-server sidecar
-        run: bun run build:opencode
+        run: |
+          cd Agent-backend && bun install --frozen-lockfile
+          cd ..
+          bun run build:opencode
 
       # Install Claude Code CLI and copy the binary
       - name: Install Claude Code CLI