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>

vector-geometry/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "luma-vector-geometry"
+version = "0.1.0"
+edition = "2024"
+rust-version = "1.88"
+publish = false
+license = "MIT"
+
+[dependencies]
+lyon_tessellation = "1.0"