Bumps [actions/cache](https://github.com/actions/cache) from 5 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

DriveButton connects a "changed" handler to the global default
GtkIconTheme but drive_button_dispose() never disconnected it. The icon
theme outlives the button, so after a button is destroyed (a volume or
mount is removed) a later "changed" emission runs the handler on freed
memory and schedules drive_button_update() via an idle source, crashing
the panel with a use-after-free.

Disconnect the handler in drive_button_dispose().

Assisted-by: Claude:claude-opus-4.8

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Add a new preference to force fixed size on all notes to prevent
resizing. Also fix a bug where notes taller than the screen height would
not display scrollbars after applet restart.

Fixes #370

When a network interface is disabled at the kernel level, the applet
tries to read from a device that no longer exist, generating continuous
warning messages in syslog.

Check if the device exists before calling glibtop_get_netload in both
is_dummy_device and get_device_info. When the device doesn't exist,
get_device_info returns a non-running device info, allowing the existing
auto-change logic to find an active device.

Fixes #688