Merge Luma launcher fork into monorepo

Move trampoline files (boot-hook, watcher, overlay) into trampoline/
subdirectory. Add upstream Luma v2.3.1 source at repo root with our
additions:

- Page::Ha (4th nav tab) with placeholder empty state
- HA tab config schema and default entity mapping (ha-home/)
- Nav keys renamed: "home" → "start", new "ha" tab between Apps and Settings
- All state.rs/view.rs/main.rs/tests.rs updated for 4-tab navigation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

trampoline/watcher.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+# Foreground watcher — subscribes to app manager events and launches Luma
+# whenever the web Home trampoline appears in the foreground.  The outer
+# loop restarts the subscription if it drops.
+
+echo $$ > /tmp/luma-watcher.pid
+
+while true; do
+  luna-send -i luna://com.webos.applicationManager/getForegroundAppInfo \
+    '{ "subscribe": true }' 2>/dev/null \
+  | while IFS= read -r line; do
+    case "$line" in
+      *com.webos.app.home*)
+        luna-send -n 1 -w 5000 -f \
+          luna://com.webos.applicationManager/launch \
+          '{ "id": "com.ecklf.luma" }' >/dev/null 2>&1
+        ;;
+    esac
+  done
+  sleep 2
+done