feat(ui): add custom application icons and branding

Add io.uchroma icon in standard hicolor sizes (16x16 through 512x512)
for proper desktop integration.

Update GTK application to use custom icon:
- Set application icon in AboutWindow
- Set window icon via set_icon_name
- Add local icon search path for development mode

Update documentation assets:
- Add logo and favicon to docs/public
- Center README header with project logo
- Update VitePress favicon configuration

Author: hyperb1iss

README.md

@@ -1,8 +1,14 @@
-## 💜 uChroma
+<p align="center">
+  <img src="docs/public/uchroma-mark.png" alt="UChroma" width="200">
+</p>
+
+<h1 align="center">uChroma</h1>
 
-**RGB Control for Razer Chroma on Linux**
+<p align="center">
+  <strong>RGB Control for Razer Chroma on Linux</strong>
+</p>
 
-<p>
+<p align="center">
   <img src="https://img.shields.io/badge/Python-3.10+-3776ab?style=for-the-badge&logo=python&logoColor=white" alt="Python">
   <img src="https://img.shields.io/badge/GTK4-Frontend-4a86cf?style=for-the-badge&logo=gtk&logoColor=white" alt="GTK4">
   <img src="https://img.shields.io/badge/D--Bus-API-e135ff?style=for-the-badge&logo=freedesktoporg&logoColor=white" alt="D-Bus">

docs/.vitepress/config.mts

@@ -9,7 +9,7 @@ export default withMermaid(
     base: '/uchroma/',
     appearance: 'dark',
 
-    head: [['link', { rel: 'icon', type: 'image/svg+xml', href: '/logo.svg' }]],
+    head: [['link', { rel: 'icon', type: 'image/png', href: '/uchroma/favicon.png' }]],
 
     vite: {
       plugins: [llmstxt()],