Desktop: "Update available" for untagged commits that have no installer

What happens The desktop app's Updates panel reports "Update available" for the newest commit on main, even when that commit has no tagged release and therefore no installer. Clicking Update does nothing: no download, no progress, no restart prompt. Quitting and relaunching leaves the build unchanged.

Steps to reproduce

1. Run the desktop app on the latest tagged release (v0.11.0 / 955e9cf).
2. Open Settings → Updates.
3. The panel lists the newest main commit as an available update.
4. Click Update, then quit and relaunch.
5. The build is still 955e9cf.

Seen twice

• 17 Sep: offered ac6d29d (a CI change to the release workflow).
• 18 Sep: offered 47c3a45 (fix(routing) #1267).

Neither has a release tag, so there is no macOS installer to fetch.

Expected Either compare the running build against the latest tagged release and stay quiet when none is newer, or label untagged commits clearly, e.g. "newer commit on main, no installer available", with the Update button disabled.

Setup

• FreeLLMAPI desktop v0.11.0 (955e9cf), macOS, Premium (live catalogue)
• No errors shown in the panel

Why it matters Both times I quit and relaunched expecting the fix I was waiting on (#1259). A user can't tell from the panel which entries are installable.