[Linuxuser67]

Summary

Fix the misleading “Couldn't check for updates” state on fresh or data-cleared Flatpak installs.

• Probe only for the presence of the required yt-dlp/ffmpeg binaries when the Media preferences page opens. Show a temporary disabled “Checking installed tools…” state instead of exposing “Check for Updates” before their presence is known.
• Show Install when the required binaries are missing.
• If the tools disappear between the presence probe and a button click, short-circuit the update flow to Install rather than querying upstream releases and falling through to the generic update-check error.
• Keep version probes and upstream release checks on-demand; this does not introduce automatic update checks on page open.

Validation

• Confirmed the failure path: a missing core binary makes resolve_libraries() return None, but the old handler still fetched release metadata and then marked the result indeterminate.
• CI will run formatting, Clippy, Rust tests, UI tests, dependency/vendor consistency, structure, and audit checks.