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

scripts/start.ps1

@@ -35,6 +35,9 @@ function Update-EnvironmentPath {
         "$env:LOCALAPPDATA\Microsoft\WinGet\Links",
         "$env:LOCALAPPDATA\Android\Sdk\platform-tools",
         "$env:ProgramFiles\Android\platform-tools",
+        "$env:ProgramFiles\nodejs",
+        "${env:ProgramFiles(x86)}\nodejs",
+        "$env:APPDATA\npm",
         "C:\ProgramData\chocolatey\bin",
         "$env:USERPROFILE\scoop\shims",
         "$env:USERPROFILE\.local\bin",
@@ -97,8 +100,39 @@ if (-not (Test-Path ".env")) {
 Write-Host "   📦 Synchronizing Python runtime and project dependencies..." -ForegroundColor Cyan
 uv sync --quiet
 
-# 6. Launch unified Showcase UI & open browser
+# 6. Check and build Showcase UI if not already compiled
+$ShowcaseIndex = "$RootDir\apps\showcase_ui\dist\frontend\browser\index.html"
+$ShowcaseIndexAlt1 = "$RootDir\apps\showcase_ui\dist\browser\index.html"
+$ShowcaseIndexAlt2 = "$RootDir\apps\showcase_ui\dist\index.html"
+if ((-not (Test-Path $ShowcaseIndex)) -and (-not (Test-Path $ShowcaseIndexAlt1)) -and (-not (Test-Path $ShowcaseIndexAlt2))) {
+    if (-not (Test-CommandExists "npm")) {
+        if (Test-CommandExists "winget") {
+            Write-Host "   ⚡ Node.js/npm not found. Installing Node.js LTS via WinGet..." -ForegroundColor Yellow
+            winget install --id OpenJS.NodeJS.LTS -e --accept-source-agreements --accept-package-agreements --silent 2>$null | Out-Null
+            Update-EnvironmentPath
+        }
+    }
+
+    if (Test-CommandExists "npm") {
+        Write-Host "   🎨 Showcase UI build not found. Compiling Angular Showcase UI..." -ForegroundColor Yellow
+        Push-Location "$RootDir\apps\showcase_ui"
+        try {
+            npm install --silent
+            npm run build
+            Write-Host "   ✔ Showcase UI compiled successfully." -ForegroundColor Green
+        } catch {
+            Write-Host "   ⚠ Failed to build Showcase UI: $_" -ForegroundColor DarkYellow
+        } finally {
+            Pop-Location
+        }
+    } else {
+        Write-Host "   ⚠ Node.js/npm not found. Please install Node.js (>= 18) to compile Showcase UI." -ForegroundColor DarkYellow
+    }
+}
+
+# 7. Launch unified Showcase UI & open browser
 Write-Host "   🚀 Launching Artemis Showcase UI & Admin Console..." -ForegroundColor Green
+Write-Host "   💡 Tip: Connect to Antigravity / Claude Desktop anytime: artemis mcp --install all" -ForegroundColor Cyan
 if ($NoOpen) {
     uv run artemis ui --port $Port --no-open
 } else {