feat(ui): ensure cross-platform one-click setup and default Showcase UI routing

- Add explicit root route (/) in server.py to guarantee Showcase UI is served by default, routing /admin to the Admin Debug Console
- Enhance dynamic Angular dist detection across multiple standard output paths
- Add automated Node.js/npm detection and installation fallbacks to start scripts and installers across macOS, Linux, and Windows
- Automatically build Showcase UI when launching via start.sh, start.bat/start.ps1, or artemis ui if frontend artifacts are missing
- Add Node.js / npm and Showcase UI status inspection rows to artemis doctor
- Support artemis mcp --install for one-click IDE integration and add make build-ui target

mcp_server/README.md

@@ -66,4 +66,14 @@ artemis mcp
 ```
 
 ### IDE Configuration
-Run `artemis mcp --generate-config all` to generate ready-to-use configuration JSON for Cursor, Claude Code, OpenClaw, and Windsurf.
+
+#### One-Click Auto Install (Recommended)
+Run the automated installer to detect and configure your IDE (Antigravity, Cursor, Claude Code/Desktop, OpenClaw):
+```bash
+artemis mcp --install all
+# Or install specifically for Antigravity:
+artemis mcp --install antigravity
+```
+
+#### Manual JSON Config Generation
+Run `artemis mcp --generate-config antigravity` (or `all`) to output ready-to-use configuration JSON with resolved `.venv` Python and project paths.