Add native Settings and complete live configuration reload

Add compact branded Settings with safe atomic edits, external config refresh and a draggable sidebar. Reconcile services, update connected displays and input devices, apply live layout policy and window rules, and resolve initial floating placement before tiled insertion. Package the Settings launcher and shared Ferese icon.

README.md

@@ -13,6 +13,34 @@ For a versioned installation alongside Plasma in SDDM, see
 
 ## Live configuration
 
+`ferese-settings` opens the native settings application, also available from
+Control Center → Settings after installation. It includes appearance presets,
+wallpaper selection, menu bar geometry, window behavior, motion, keyboard/mouse,
+custom shortcut editing, login items, and existing display profiles. Changes save
+automatically; text fields save on Enter or when leaving the field. Sliders save
+when released. Settings also refreshes after external config edits, preserving
+active drafts. Display profiles, touchpad options, and login items update live.
+
+The app validates changes with `ferese --check-config PATH` before atomically
+replacing your file, preserves comments and unrelated keys, and keeps a
+`config.toml.settings-backup`. Undo restores the previous save; external edits
+require Reload before saving. Search filters settings categories. To preview
+against a disposable config without changing your desktop config:
+
+```sh
+cargo build -p ferese -p ferese-settings --locked
+target/debug/ferese-settings --config /tmp/ferese-settings-preview.toml
+```
+
+The GUI is not a replacement for every advanced config option: adding display
+profiles, arranging outputs, new shortcut definitions, and window rules remain
+in `config.toml`. Theme presets update palette and focus-gradient colors without
+replacing custom rules, bindings, wallpaper, or layout settings.
+
+New installations float Settings by default. To do the same in an existing
+config, add a `[[window_rules]]` entry with `app_id = "dev.ferese.Settings"`
+and `floating = true`.
+
 Saving `~/.config/ferese/config.toml` (or `$XDG_CONFIG_HOME/ferese/config.toml`)
 reloads it automatically. Atomic editor saves are supported and bursts are
 debounced. Invalid edits keep the last working compositor and shell config;
@@ -24,9 +52,11 @@ Live sources are limited to 60 KiB for safe delivery over the private protocol.
 Appearance, fonts, wallpaper, animations, keybindings, keyboard layout/repeat,
 gaps, scrolling focus policy/default widths, and bar geometry reload live.
 Wallpaper decoding stays off the render thread and keeps the old image until
-the replacement is ready. Existing windows, widths and layouts are preserved;
-layout-mode defaults and initial window rules affect new workspaces/windows.
-Output profiles and touchpad changes apply on reconnect or session restart.
+the replacement is ready. Layout-mode changes convert existing workspaces;
+default-width changes update columns using the previous default, preserving
+custom widths. Changed window rules are reapplied to existing matching windows.
+Output profiles and touchpad changes apply immediately. Display changes retain
+output/workspace identity; configurations with no usable output are rejected.
 The compositor and shell need one initial update/restart to enable this feature.
 
 ## Session services and locking
@@ -36,6 +66,7 @@ The compositor and shell need one initial update/restart to enable this feature.
 ```toml
 [[autostart]]
 command = ["awari"]
+enabled = true
 restart = true
 
 [[autostart]]
@@ -46,7 +77,8 @@ restart = true
 Services are session-owned, reaped, and restarted with a five-second retry delay.
 They receive the correct public Wayland display without private shell privileges.
 Nested previews skip them unless `nested = true` is explicitly configured.
-Autostart changes require a session restart; live config edits do not restart services.
+Autostart changes reconcile live: unchanged commands keep their processes,
+new/enabled items start, and disabled/removed commands stop without blocking rendering.
 Run foreground daemons here, not commands that fork themselves into the background.
 
 Ferese implements `ext-session-lock-v1`. While locked, only lock surfaces over an
@@ -290,8 +322,7 @@ no image reload or full-screen shell buffers. The launched shell receives
 `FERESE_COMPOSITOR_WALLPAPER=1` to disable its redundant wallpaper surfaces.
 When no valid image path is configured, the shell's existing fallback remains.
 
-Keyboard settings reload live. Direct-session touchpad settings apply on device
-reconnect or session restart:
+Keyboard and direct-session touchpad settings reload live:
 
 ```toml
 [input]
@@ -343,9 +374,8 @@ position = [0, 0]
 Unspecified connected outputs remain enabled with their preferred mode, scale
 `1.0`, normal transform, and automatic horizontal placement. Supported
 transforms are `normal`, `rotate_90`, `rotate_180`, `rotate_270`, `flipped`,
-and their rotated flipped variants. Output configuration is applied at startup
-and on hotplug. Reloaded output profiles take effect on reconnect or session
-restart; they do not change an already-connected output's mode.
+and their rotated flipped variants. Output configuration is applied at startup,
+on hotplug, and live reload, including modes, scale, transform, and position.
 
 On DRM, closing the laptop lid disables internal panels when a usable external
 output is available. With no usable external output, the panel stays enabled;