Refine notification center and configure native notifications

Keep notification actions and dismiss controls visible, compact and animate history, and add themed icon controls and grouping.

Include notification settings, session integration and documentation, on-demand workspaces, and performance baseline notes.

docs/configuration.md

@@ -379,3 +379,11 @@ The installed session launcher enables screencopy for screenshots unless
 `FERESE_ENABLE_SCREENCOPY=0` is explicitly set in its environment.
 Text input is available by default; Ctrl+Alt+Escape releases an active shortcut
 inhibitor. Use `feresectl --help` for runtime control commands.
+
+## Notifications
+
+Settings → Notifications controls popups, Do Not Disturb, and the default timeout. See [Notifications](notifications.md) for KDL options and app behavior.
+
+A single-output session starts with workspace 1. Numbered workspace shortcuts create
+workspaces on demand; switching forward past the last workspace also creates the
+next one. Additional displays receive their own workspace.