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.

pkgs/nomarchy-install/default.nix

@@ -15,6 +15,7 @@
 , pciutils         # lspci
 , usbutils         # lsusb (fingerprint-reader VID probe; sysfs is the fallback)
 , btrfs-progs      # inspect-internal map-swapfile (hibernation offset)
+, mesa-demos       # glxinfo — OpenGL probe for Ghostty floor (needs 4.3)
 , xkeyboard_config # human-readable installed layout/variant catalog
   # Baked metadata — what this installer installs and where it came from.
 , templateDir              # templates/downstream (home.nix, theme-state.json)
@@ -64,6 +65,7 @@ stdenvNoCC.mkDerivation {
       --prefix PATH : ${lib.makeBinPath [
         bash gum disko whois git python3
         util-linux gptfdisk parted cryptsetup lvm2 pciutils usbutils btrfs-progs
+        mesa-demos
       ]} \
       --set NOMARCHY_INSTALL_SHARE "$share" \
       --set NOMARCHY_XKB_RULES ${xkeyboard_config}/share/X11/xkb/rules/base.lst \