CmdPal: Add support for the voice input

### Description of the new feature / enhancement

Add first-class support for voice input and speech recognition.

- Add a new activation shortcut(s) to trigger voice input.
- Add UI button and keyboard shortcut to trigger voice input in place.
- Allow users to choose between toggle mode and push-to-talk mode.
- Support multiple speech recognition providers:
- Built-in system speech recognition.
- External speech recognition services.
- External apps, such as Handy.

### Scenario when this would be used?

This should make voice input a native interaction model instead of requiring users to rely only on external tools or OS-level workarounds.

### Supporting information

_No response_