feat(launcher): wire panels into master-detail layout

Replaces the centered-button list with a 1/3 list + 2/3 detail split
driven by panels/list.lua and panels/detail.lua. The shared ctx_panels
table threads UI state (selected_entry, scroll_y, modal_open, etc.)
through both panels. Existing dep + update checks remain on the module
entries; FSM and ESC-quit flow unchanged. Detail-panel content is still
a stub until L.4-L.7.

manifest.module

@@ -1,6 +1,6 @@
 {
   "id": "lib-management.launcher",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "kind": "module",
   "api": "^0.1",
   "ci_frames": 10,