chore: System updates and config tweaks

Updated all flake inputs and applied srveral improvements to the
system configurations.

*** Updates
- Ran =flake update= to bring all dependencies to their latest
  versions.
- Pinned =lix-module= to the stable =release-2.93= branch to
  prevent breakages from its main branch.

*** System Configuration
- ssh: Reworked the client configuration to use a global =*= match
  block for secure defaults. Disabled the default home-manager
  config for removing nixpkgs' wrannings.
- intel-vaapi-driver: Enabled =enableHybridCodec= override to avoid
  to build whole package from scratch.
- kde: Forced the Qt platform theme to =kde= to fix a visual bug
  with Stylix.
- onnxruntime: Disabled CUDA/NCCL support to avoid to build the
  whole package from scratch.

*** Application Changes
- firefox: Switched the default browser package to =firefox-beta=
  across the entire configuration (NixOS, home-manager, and niri).
- editor: Removed =hurl= and =cmake-language-server= from the
  editor runtime environment for broken packages.

nixos/modules/gui/niri.nix

@@ -42,28 +42,28 @@ in
             "com.system76.CosmicFiles.desktop"
           ];
           "x-scheme-handler/about" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "x-scheme-handler/ftp" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "x-scheme-handler/http" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "x-scheme-handler/https" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "x-scheme-handler/mailto" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "x-scheme-handler/tg" = [ "telegramdesktop.desktop" ];
           "x-scheme-handler/unknown" = [
-            "firefox.desktop"
+            "firefox-beta.desktop"
             "chromium-browser.desktop"
           ];
           "image/gif" = [