feat: ship manifest.launcher.md for master-detail launcher

manifest.launcher.md

@@ -0,0 +1,19 @@
+---
+{"summary":"Sporel Launcher — module browser","author":"calic","tags":["host","launcher"],"teaser_images":[]}
+---
+
+# Sporel Launcher
+
+Master-detail module browser. Lists every installed module on the
+left, shows per-module hero, description, dependencies, and a Launch
+button on the right.
+
+## How to use
+
+- Click a module to see its details.
+- Click Launch Module to start it.
+- ESC returns to this launcher from any module.
+
+## What's next
+
+See the News entry for in-progress + planned features.