* fix(text-injection): wait for shortcut modifiers to release before Wayland inject
Injection emits real key events, so a held modifier from a toggle/PTT shortcut
(e.g. Alt from Alt+R) turns the simulated Ctrl+V paste into Ctrl+Alt+V and
nothing pastes — while the clipboard still shows the text. Because transcription
can finish in tens of ms, the user is often still holding the key, causing
intermittent paste failures.
Poll evdev for held modifier keycodes and defer injection until they clear
(bounded by VOCALINUX_INJECT_MODIFIER_WAIT, default 1.0s, 0 disables). Returns
immediately when nothing is held, so no added latency in the common case.
* style: black-format injection modifier-wait test
* test: cover _held_modifier_keycodes evdev scanning (patch coverage)
* test: cover error paths in _held_modifier_keycodes
* fix(text-injection): treat non-finite modifier-wait env as default
float('inf') parses cleanly and is > 0, so it slipped past the guard and made
the wait deadline infinite -- a held modifier could block injection forever
(nan was nonsensical too). Sanitize VOCALINUX_INJECT_MODIFIER_WAIT via a helper
that falls back to the 1.0s default for non-finite values. Regression tests
added, including that 'inf' still terminates.
Addresses maintainer review on PR #494.
