fix(hotkeys): handle shortcuts in capture phase (#1314)

[richardmilles]

Register global hotkeys in the capture phase so combos like Ctrl+Alt+P call preventDefault before the browser default.
Fixes #1314

[perber]

Thanks for the fix! CI's test-frontend job was failing on the new registers the keydown listener in the capture phase test — HotKeyHandler calls useAppMode() → useLocation(), which needs router context, but that test rendered it without one (unlike the other tests in the file). Pushed a small follow-up commit wrapping it in MemoryRouter to match the rest of the file; all 3 tests pass now.