🐛 Bug - Browser notifications do not display user mentions

[SigmaTel71]

Describe the bug
User handles are not formatted properly to be rendered in notification flyouts from browser.

To Reproduce
Steps to reproduce the behavior:

1. Enable browser notification
2. Put Valour in background tab
3. Wait for someone to send you a message with ping
4. See error

Expected behavior
User handles are visible

Screenshots

System Information:

• OS: Windows 11 Pro 25H2 (amd64)
• Valour Version: Valour Alpha V0.5.20.0 (94302bb)
• Valour Platform: Web
  • Browser: Vivaldi 7.9

Additional context

Browser properties

Version: 7.9.3970.41 (Official build) (64 bit)
Chromium Version: 146.0.7680.158
Command line: "D:\Program Files\Vivaldi Portable\Application\vivaldi.exe" --vivaldi-standalone --flag-switches-begin --disable-quic --flag-switches-end --origin-trial-disabled-features=CanvasTextNg|WebAssemblyCustomDescriptors --flag-switches-begin --disable-quic --flag-switches-end --disable-smooth-scrolling