#### Brief overview of PR changes/additions
- The notepad and IRC client are parentless windows freed only in
`Host::closeChildren()`; a `Host` destroyed without that call orphaned
them. `~Host()` now closes and deletes them, nulling each `QPointer`
first so both teardown paths stay single-delete. Closing (not just
deleting) the notepad also saves the notes and window state.
- The toolbars are not leaked at exit, but survived their profile on
screen holding a freed `TAction`; `~Host()` now deletes them
synchronously.
#### Motivation for adding to Mudlet
Same defect class PR #9700 "fix: trigger editor and deleted item
subtrees leaking memory" fixed for the editor. Two narrow production
paths reach `~Host()` without `closeChildren()` (`requestClose()`
returns early when `mpConsole` is already gone, and `~HostManager` runs
from `~mudlet`), and the test harness takes the second on every run.
#### Other info (issues closed, discussion etc)
Test case: new `HostChildTeardownTest` - three teardown orderings, each
fails without the fix; under ASan+LSan the binary goes from 851,208 to
3,334 leaked bytes (residue is the settings floor fixed in #9694). 79/79
functional tests pass twice; profile-close/quit with the notepad open
are clean under ASan on Xvfb.
Assisted-by: Claude:claude-opus-5
