Initial support for application specific overrides.

README.md

@@ -14,6 +14,7 @@ See the [user manual](docs/user.md) for detailed usage documentation.
 - Cursor, table, and highlight tracking.
 - Desktop and laptop keyboard layouts, with an interactive tutorial.
 - A keyboard-operated settings menu and quick settings shortcuts.
+- Temporary built-in application overrides for Ninjam and NetworkManager's nmtui.
 - Speech Dispatcher and hardware speech synthesizer support.
 - Sound icons, progress tones, and indentation and text attribute feedback.
 - Multiple clipboards, optional persistent history, and X clipboard synchronization.
@@ -111,6 +112,7 @@ Shortcuts shared by both layouts:
 - **Fenrir+H** or **Fenrir+F1**: enter the tutorial. Press command shortcuts to
   hear their descriptions, or browse with the arrow keys. Escape exits.
 - **Fenrir+S**: open the spellcheck menu.
+- **Fenrir+A**: select an application override; choose **Default** to clear it.
 - **Fenrir+Control+E**: open the emoji picker.
 - **Fenrir+T**: announce the time; press twice quickly for the date.
 - **Fenrir+F4**: toggle mute.
@@ -151,6 +153,13 @@ Quick settings are available without opening the menu:
 Quick settings take effect during the session; save them to keep them for the
 next launch.
 
+Application overrides are selected manually and never saved. While an override
+is selected, saving reports **Save unavailable.** A detected return to a shell
+prompt, selecting Default, or restarting Fenrir clears its temporary changes.
+See [application overrides](docs/user.md#application-overrides) for details and
+Ninjam's temporary region shortcuts. In the laptop layout, reading the current
+attributes now uses **Fenrir+Shift+A**.
+
 ### Configuration files
 
 Fenrir uses TOML. The annotated [settings.toml](config/settings/settings.toml)