Merge remote-tracking branch 'origin/v0.7/ipc' into v0.7/singletagset-pertag-ipc-compat

Merge branch 'v0.7/singletagset-ipc' into v0.7/patched-base

Merge branch 'v0.7/ipc' into v0.7/patched-base

singletagset-ipc

- Correctly identify vacant tags,
- Add active_other state that says a given tag is active on another monitor

implement dwl-ipc-unstable-v2 https://codeberg.org/dwl/dwl-patches/wiki/ipc

implement dwl-ipc-unstable-v2 https://codeberg.org/dwl/dwl-patches/wiki/ipc