feat(terminal): themed Kitty when OpenGL < 4.3 (#95)

Ghostty needs OpenGL 4.3; older GPUs (Intel HD 4000) top out at 4.2.
Installer probes glxinfo and writes settings.terminal=kitty into
theme-state when below the floor. modules/home/kitty.nix enables Kitty
with the same palette, mono font, and opacity as Ghostty so the fallback
still looks like Nomarchy.

Default machines stay Ghostty-only (no kitty in the HM closure). Doctor
and calendar still invoke Ghostty by class — V3 on Acer for SUPER+Return.

Verified: V0 flake check; installer-safety; HM with terminal=kitty builds
themed kitty.conf + TERMINAL=kitty; default template has no kitty bin.

modules/home/default.nix

@@ -11,6 +11,7 @@
     ./hyprland.nix
     ./waybar.nix
     ./ghostty.nix
+    ./kitty.nix     # themed fallback when Ghostty cannot run (OpenGL < 4.3)
     ./btop.nix
     ./rofi.nix      # launcher theming + the nomarchy-menu dispatcher
     ./swaync.nix    # notification daemon, themed from the same JSON