The single global "Save endpoints" button sat far below the fold and the
per-card "Test endpoint" button probed the server-stored settings, so it
ignored unsaved form edits. Replace each endpoint card's "Test endpoint"
button with a combined "Save and test" button that persists the whole form
first and only runs the card's connection probe on a successful save; the
global "Save endpoints" button is kept for save-only.
- Add handleSaveAndTest: save (rethrows on failure) then probe; skip the
test if the save fails (the mutation already surfaces the error).
- Add savingTestCapability state so only the clicked card spins during the
shared save while all save controls stay disabled (no concurrent saves).
- Reset the previous probe result when a new save+test starts.
- Add the "Save and test" en-US translation key.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>