fix(overlay): keep Hyprland IPC env when forcing mpv X11 backend

- Stop stripping HYPRLAND_INSTANCE_SIGNATURE in applyX11EnvOverrides so the overlay can use hyprctl to lift Hyprland's fullscreen input block
- Fixes the overlay becoming unclickable over fullscreen mpv with mpv.backend: x11
- Update launcher and backend tests, add changelog fragment

changes/hyprland-x11-fullscreen-overlay-input.md

@@ -0,0 +1,4 @@
+type: fixed
+area: overlay
+
+- Fixed the overlay (subtitles and sidebar) becoming unclickable after mpv goes fullscreen on Hyprland with `mpv.backend: x11`. The launcher no longer strips `HYPRLAND_INSTANCE_SIGNATURE` from the X11 environment, so the overlay can lift Hyprland's fullscreen input block again.

launcher/mpv.test.ts

@@ -179,7 +179,8 @@ test('buildMpvEnv forces X11 by dropping Wayland hints when backend resolves to
     assert.equal(env.DISPLAY, ':1');
     assert.equal(env.WAYLAND_DISPLAY, undefined);
     assert.equal(env.XDG_SESSION_TYPE, 'x11');
-    assert.equal(env.HYPRLAND_INSTANCE_SIGNATURE, undefined);
+    // The overlay inherits this env and needs hyprctl for its XWayland window.
+    assert.equal(env.HYPRLAND_INSTANCE_SIGNATURE, 'hypr');
     assert.equal(env.SWAYSOCK, undefined);
   });
 });

src/shared/mpv-x11-backend.test.ts

@@ -82,7 +82,7 @@ test('shouldForceX11MpvBackend honors explicit x11 and auto modes', () => {
   });
 });
 
-test('applyX11EnvOverrides strips Wayland hints and pins session type to x11', () => {
+test('applyX11EnvOverrides strips Wayland hints, keeps Hyprland IPC, and pins session type to x11', () => {
   const env = {
     DISPLAY: ':1',
     WAYLAND_DISPLAY: 'wayland-0',
@@ -94,7 +94,7 @@ test('applyX11EnvOverrides strips Wayland hints and pins session type to x11', (
   assert.equal(result, env); // mutates in place
   assert.equal(result.DISPLAY, ':1');
   assert.equal(result.WAYLAND_DISPLAY, undefined);
-  assert.equal(result.HYPRLAND_INSTANCE_SIGNATURE, undefined);
+  assert.equal(result.HYPRLAND_INSTANCE_SIGNATURE, 'hypr');
   assert.equal(result.SWAYSOCK, undefined);
   assert.equal(result.XDG_SESSION_TYPE, 'x11');
 });

src/shared/mpv-x11-backend.ts

@@ -89,10 +89,14 @@ export function shouldForceX11MpvBackend(
 /**
  * Strip Wayland/compositor hints and pin the session type to X11 on the given env
  * object (mutates in place and returns it) so a child mpv process picks XWayland.
+ *
+ * HYPRLAND_INSTANCE_SIGNATURE is kept: the overlay app inherits this env through the
+ * mpv plugin, and Hyprland still manages its XWayland windows. Without hyprctl access
+ * the overlay cannot lift Hyprland's fullscreen input block, so it stays visible but
+ * unclickable over fullscreen mpv.
  */
 export function applyX11EnvOverrides(env: NodeJS.ProcessEnv): NodeJS.ProcessEnv {
   delete env.WAYLAND_DISPLAY;
-  delete env.HYPRLAND_INSTANCE_SIGNATURE;
   delete env.SWAYSOCK;
   env.XDG_SESSION_TYPE = 'x11';
   return env;