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>

src/vector.rs

@@ -0,0 +1,84 @@
+//! Precompiled SVG triangle geometry, uploaded once without image textures.
+use gl::types::GLuint;
+use std::{fs, path::Path};
+
+pub struct Mesh {
+    pub buffer: GLuint,
+    pub width: f32,
+    pub height: f32,
+    pub vertices: i32,
+    pub bytes: usize,
+}
+
+impl Mesh {
+    pub fn load(path: &Path) -> Result<Self, String> {
+        let bytes =
+            fs::read(path).map_err(|e| format!("Vector artwork {}: {e}", path.display()))?;
+        if bytes.len() < 20 || &bytes[..8] != b"LUMAVEC1" {
+            return Err(format!("Invalid vector artwork header: {}", path.display()));
+        }
+        let float = |offset| f32::from_le_bytes(bytes[offset..offset + 4].try_into().unwrap());
+        let width = float(8);
+        let height = float(12);
+        let count = u32::from_le_bytes(bytes[16..20].try_into().unwrap()) as usize;
+        if !width.is_finite()
+            || !height.is_finite()
+            || width <= 0.
+            || height <= 0.
+            || count == 0
+            || count > 1_000_000
+            || !count.is_multiple_of(3)
+            || bytes.len() != 20 + count * 36
+        {
+            return Err(format!(
+                "Invalid vector artwork dimensions: {}",
+                path.display()
+            ));
+        }
+        let vertices: Vec<f32> = bytes[20..]
+            .chunks_exact(4)
+            .map(|chunk| f32::from_le_bytes(chunk.try_into().unwrap()))
+            .collect();
+        if vertices.iter().any(|value| !value.is_finite()) {
+            return Err(format!(
+                "Invalid vector artwork coordinates: {}",
+                path.display()
+            ));
+        }
+        Self::upload(width, height, &vertices)
+    }
+
+    pub fn upload(width: f32, height: f32, vertices: &[f32]) -> Result<Self, String> {
+        let count = vertices.len() / 9;
+        if count == 0 || !count.is_multiple_of(3) || vertices.len() != count * 9 {
+            return Err("Invalid vector buffer vertex count".into());
+        }
+        if vertices.iter().any(|value| !value.is_finite()) {
+            return Err("Invalid vector buffer coordinates".into());
+        }
+        let mut buffer = 0;
+        unsafe {
+            gl::GenBuffers(1, &mut buffer);
+            gl::BindBuffer(gl::ARRAY_BUFFER, buffer);
+            gl::BufferData(
+                gl::ARRAY_BUFFER,
+                std::mem::size_of_val(vertices) as isize,
+                vertices.as_ptr().cast(),
+                gl::STATIC_DRAW,
+            );
+        }
+        Ok(Self {
+            buffer,
+            width,
+            height,
+            vertices: count as i32,
+            bytes: count * 36,
+        })
+    }
+}
+
+impl Drop for Mesh {
+    fn drop(&mut self) {
+        unsafe { gl::DeleteBuffers(1, &self.buffer) };
+    }
+}