2.0

• Migrate to GTK-4
• Modernize the look of dialogs
• Make spell-check dialog text directly editable
• Combine window titlebar and toolbar into a header bar
• Allow overriding encoding and newlines when saving (#137)
• Follow the system-wide dark theme preference (GTK ≥ 4.20), overridable with the general.theme config file option, which replaces the previous general.dark_theme option
• Drop support for extensions; replace the custom-framerates extension with config file option editor.custom_framerates
• Switch the integrated video player from gtksink to gtk4paintablesink
• Use a one-second preview offset for all external video players
• Raise Python dependency to ≥ 3.10
• Raise PyGObject dependency to ≥ 3.40
• Raise GTK dependency to ≥ 4.12
• Raise GStreamer dependency to ≥ 1.18
• Replace gspell dependency with libspelling ≥ 0.2
• Fully rewritten installation mechanism, see README.md and PACKAGING.md