* fix(ibus): capture current engine during prepare_engine for scoped activation
Two bugs were causing IBus injection to fail and fall back to ydotool:
1. get_current_engine() returned empty string (falsy) when 'ibus engine'
output was empty, instead of None. This caused inject_text() to think
no engine was available.
2. prepare_engine() didn't capture the current IBus engine, so when
inject_text() tried to get it at runtime, it would fail on systems
where 'ibus engine' returns empty output.
Fix: get_current_engine() now returns None for empty output. prepare_engine()
captures the current engine before starting the Vocalinux process. inject_text()
uses the captured _previous_engine as fallback when get_current_engine() fails.
Fixes the regression from PR #457 where IBus injection would fail with:
WARNING Could not determine current IBus engine
ERROR IBus engine instance is not active and the previous engine
could not be captured safely
* fix(ibus): always activate engine for injection on Wayland
On Wayland, 'ibus engine' returns empty output, so get_current_engine()
returns None. The previous code would skip activation when it couldn't
determine the current engine, causing injection to fail and fall back
to ydotool.
Now we always activate the Vocalinux engine when it's not active,
regardless of whether we can capture the previous engine. If we couldn't
capture it, we simply don't restore anything after injection.
This fixes the regression where IBus injection would fail with:
WARNING Could not determine current IBus engine
ERROR IBus engine instance is not active and the previous engine
could not be captured safely
Fixes#458
* test(ibus): add missing mocks for is_engine_active and get_current_engine
Existing tests didn't mock is_engine_active() and get_current_engine(),
which are now called at the start of inject_text() for scoped activation.
This caused CI failures on Python 3.9-3.13 where the unmocked calls
would try to run 'ibus engine' and get unexpected results.
