fix(kodi): patch stremio CEF to support HiDPI scaling via env var

The beta.13 clap parser ignores unknown --force-device-scale-factor flags
and CEF Args::new() starts empty, so CLI flags never reach the CEF subprocess.
Patch src/webview/mod.rs to read STREMIO_FORCE_DEVICE_SCALE_FACTOR and pass
it to CEF via append_switch_with_value. Remove failed GTK4/master branch
build attempt (requires GTK 4.22 not yet in nixpkgs).

flake.nix

@@ -82,14 +82,16 @@
             };
           };
           custom = prev.callPackage ./packages { };
+          # Patch stremio-linux-shell to support STREMIO_FORCE_DEVICE_SCALE_FACTOR
+          # env var, which passes --force-device-scale-factor to the CEF subprocess
+          # for HiDPI display scaling control
+          stremio-linux-shell = prev.stremio-linux-shell.overrideAttrs (old: {
+            patches = (old.patches or []) ++ [
+              ./packages/stremio-linux-shell/force-device-scale-factor.patch
+            ];
+          });
           # Compatibility: bitwarden renamed to bitwarden-desktop in unstable
           bitwarden-desktop = prev.bitwarden-desktop or prev.bitwarden;
-          # Override stremio-linux-shell with custom GTK4/master branch version
-          # Use nixpkgs-unstable for Rust 1.92+ support required by master branch
-          stremio-linux-shell = (import inputs.nixpkgs-unstable {
-            system = prev.stdenv.hostPlatform.system;
-            config.allowUnfree = true;
-          }).callPackage ./packages/stremio-linux-shell { };
         });
 
       # Shared home-manager configuration factory
@@ -122,10 +124,6 @@
         (ufinal: uprev: {
           claude-code = uprev.callPackage ./packages/claude-code { };
         })
-        # Override stremio-linux-shell with custom GTK4/master branch version
-        (ofinal: oprev: {
-          stremio-linux-shell = ofinal.custom.stremio-linux-shell;
-        })
       ];
 
       nixosModules = [