df58d98adc
Adds src/lib/utils/hotkeyValidity.ts with validateHotkey(combo, os)
and wires it into HotkeyRecorder.svelte. Rules:
- X11/Wayland/Linux: reject single-key combos unless the trigger
is F13..F24 (the conventional global-shortcut escape hatch).
- Windows: reject combos whose only modifier is a right-hand
variant (RCtrl/RAlt) — matches Handy #966's failure mode where
RegisterHotKey silently ignores them.
- macOS: reject Fn-only combos and bare-key combos (non-function
keys).
- unknown OS: pass through — better to ship a flawed combo than
reject one we can't validate.
When validation fails, the recorder leaves the previous known-good
hotkey intact and surfaces an inline warning-coloured sentence
explaining why, with actionable copy ("add a modifier", "use the
left-hand equivalent", etc.). The save button disappears because
settings.globalHotkey is never written to — no state drift.
Matches Handy #917 / #1019 / #966 / #956, brief item #5.
Co-authored-by: jars <jakejars@users.noreply.github.com>