feat(input): opt-in WebKitGTK focus repaint workaround for Linux (#342, #782) (#884)

* feat(input): opt-in WebKitGTK focus repaint workaround for Linux (#342, #782)

Some Linux users on WebKitGTK 2.50.x report a freeze when clicking
text fields: the field receives focus (right-click paste still works)
but the canvas never redraws until the window is resized. Likely a
layer-flush / composition scheduling bug in 2.50.x's Skia rendering
pipeline.

Off by default. When enabled in Settings -> System -> Behavior, every
input/textarea focus triggers a sync reflow read plus a one-frame
translateZ(0) toggle on the input's parent so WebKit re-evaluates the
layer tree. Side-effect: search-icon siblings flicker briefly on
focus -- accepted trade-off, only paid by users who opt in.

The toggle row is gated on IS_LINUX and sits next to the existing
Linux WebKitGTK options. The effect subscribes to the auth store and
re-attaches the focusin handler whenever the flag flips, so toggling
off cleanly removes the listener.

* i18n(settings): linux input repaint toggle in all locales

Adds linuxWebkitInputForceRepaint label + description across en, de,
fr, es, nl, nb, ro, zh, ru.

* docs(release): CHANGELOG and credits for linux input freeze workaround (PR #884)

src/store/authStore.ts

@@ -79,6 +79,7 @@ export const useAuthStore = create<AuthState>()(
       preloadMiniPlayer: false,
       linuxWebkitKineticScroll: true,
       linuxWaylandTextRenderProfile: 'sharp',
+      linuxWebkitInputForceRepaint: false,
       loggingMode: 'normal',
       nowPlayingEnabled: false,
       lyricsServerFirst: true,

src/store/authStoreTypes.ts

@@ -136,6 +136,11 @@ export interface AuthState {
   linuxWebkitKineticScroll: boolean;
   /** Linux Wayland + GPU compositing: WebKit text rasterisation profile (live, no restart). */
   linuxWaylandTextRenderProfile: LinuxWaylandTextRenderProfile;
+  /** Linux WebKitGTK 2.50.x text-input repaint hang workaround (issues #342, #782).
+   *  When true, toggles a one-frame transform on the focused input's parent so WebKit
+   *  re-evaluates the layer tree. Off by default — the side-effect is a brief flicker
+   *  on focus, accepted trade-off for the affected users. */
+  linuxWebkitInputForceRepaint: boolean;
   /** Runtime backend logging level. */
   loggingMode: LoggingMode;
   nowPlayingEnabled: boolean;
@@ -310,6 +315,7 @@ export interface AuthState {
   setPreloadMiniPlayer: (v: boolean) => void;
   setLinuxWebkitKineticScroll: (v: boolean) => void;
   setLinuxWaylandTextRenderProfile: (v: LinuxWaylandTextRenderProfile) => void;
+  setLinuxWebkitInputForceRepaint: (v: boolean) => void;
   setLoggingMode: (v: LoggingMode) => void;
   setNowPlayingEnabled: (v: boolean) => void;
   setLyricsServerFirst: (v: boolean) => void;

src/store/authUiAppearanceActions.ts

@@ -22,6 +22,7 @@ export function createUiAppearanceActions(set: SetState): Pick<
   | 'setPreloadMiniPlayer'
   | 'setLinuxWebkitKineticScroll'
   | 'setLinuxWaylandTextRenderProfile'
+  | 'setLinuxWebkitInputForceRepaint'
   | 'setSeekbarStyle'
   | 'setQueueNowPlayingCollapsed'
   | 'setQueueDurationDisplayMode'
@@ -45,6 +46,7 @@ export function createUiAppearanceActions(set: SetState): Pick<
     setPreloadMiniPlayer: (v) => set({ preloadMiniPlayer: v }),
     setLinuxWebkitKineticScroll: (v) => set({ linuxWebkitKineticScroll: v }),
     setLinuxWaylandTextRenderProfile: (v) => set({ linuxWaylandTextRenderProfile: v }),
+    setLinuxWebkitInputForceRepaint: (v) => set({ linuxWebkitInputForceRepaint: v }),
     setSeekbarStyle: (v) => set({ seekbarStyle: v }),
     setQueueNowPlayingCollapsed: (v) => set({ queueNowPlayingCollapsed: v }),
     setQueueDurationDisplayMode: (v) => set({ queueDurationDisplayMode: v }),