Add Odin 3 controller artwork and glyph selector

[enjihn]

Summary

• Bundle Odin 3 controller artwork and button glyphs with Armada Control
• Select the theme automatically through the Odin 3 device profile
• Add Monochrome and Rainbow face-button options
• Apply the theme across Steam, QAM, and overlay windows
• Preserve the upstream MIT license and attribution

Scope

The theme is enabled only when the device profile reports AYN Odin 3. Other devices retain Steam's existing controller artwork and glyphs.

The assets are bundled into Armada Control. CSS Loader and a separate theme installation are not required. If Decky or Armada Control is unavailable, Steam continues using its stock glyphs.

Validation

• Controller glyph regression tests passed
• Armada Control production build passed
• Clean merge preview against current main
• Verified Odin-only asset and device-profile scope
• Verified PNG structure, checksums, stylesheet references, and bundled output

This is a draft while the complete Odin 3 image receives fresh-install acceptance testing.