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>

Wire up the existing but unused "icon" GSettings key in the profile
schema so that each profile can specify a window icon. Also adds
a profile option with a file chooser.

When switching tabs, the window icon updates to match the active tab's
profile icon. Icons set via the --icon CLI option take precedence over
profile icons for the lifetime of the window.

Fixes #62

VTE maintains a two-layer color system where colors set via OSC 10/11
escape sequences take precedence over colors set via the API When
switching profiles, the API-layer colors were updated but any active OSC
overrides would persist, causing the profile's colors to be ignored.
This feeds OSC 110/111 reset sequences after setting profile colors to
clear the override layer.

Use the current directory URI (set by the shell via OSC 7 escape
sequence) to determine the working directory for new tabs, instead of
reading /proc. This works inside tmux/screen/sudo, preserves symlink
components, and is consistent with other VTE-based terminal emulators.

The /proc-based detection is kept as a fallback for shells that don't
emit OSC 7 (e.g. vte.sh is not sourced). The initial working directory
is used as a final fallback, and the separate _with_fallback variant is
folded into the main function so all callers benefit from the complete
fallback chain.

Adapted from https://gitlab.gnome.org/GNOME/gnome-terminal/-/commit/cf3cad87

Fixes #195

The built-in color scheme dropdown always showed "Custom" when reopening
the profile editor. Two bugs were present:

- color comparison was called as pointer-to-pointer comparison, which
  always fails.

- gdk_rgba_equal does exact floating-point comparison, which is too
  strict for colors that have been round-tripped through GSettings
  string serialization. Using the fuzzy rgba_equal function fixes that.

Fixes #486