OATControl V1.2.1.0 Release

• Automatic update checking for desktop app and firmware (GitHub releases).
• Update dialog with themed markdown changelog and download with progress bar.
• Firmware update badge on Mount Settings button and update link in Settings.
• "Skip This Version" to suppress notifications for a specific release.
• "Check For Updates" button in App Settings with inline result.
• Update checks throttled to once per 24 hours. Manual check bypasses throttle.
• Fault-tolerant — all network calls fire-and-forget with 5-second timeouts.