chore: remove kit stack

Remove kit service and related configuration:
- Removed kit from compose includes
- Deleted kit/compose.yaml (landing, vert, pastel, stirling, units, draw, figlet)
- Removed KIT env vars from arty.yml

Kit services were stateless and don't require data migration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

arty.yml

@@ -121,24 +121,6 @@ envs:
     JOPLIN_TRAEFIK_HOST: joplin.pivoine.art
     JOPLIN_APP_PORT: 22300
     JOPLIN_DB_NAME: joplin
-    # Kit (combines Vert and Paint with landing page)
-    KIT_TRAEFIK_ENABLED: true
-    KIT_COMPOSE_PROJECT_NAME: kit
-    KIT_TRAEFIK_HOST: kit.pivoine.art
-    KIT_LANDING_IMAGE: ghcr.io/valknarness/kit-ui:latest
-    KIT_VERT_IMAGE: ghcr.io/vert-sh/vert:latest
-    KIT_VERT_TRAEFIK_HOST: vert.kit.pivoine.art
-    KIT_PASTEL_API_IMAGE: ghcr.io/valknarness/pastel-api:latest
-    KIT_PASTEL_UI_IMAGE: ghcr.io/valknarness/pastel-ui:latest
-    KIT_PASTEL_TRAEFIK_HOST: pastel.kit.pivoine.art
-    KIT_STIRLING_IMAGE: frooodle/s-pdf:latest
-    KIT_STIRLING_TRAEFIK_HOST: stirling.kit.pivoine.art
-    KIT_UNITS_IMAGE: ghcr.io/valknarness/units-ui:latest
-    KIT_UNITS_TRAEFIK_HOST: units.kit.pivoine.art
-    KIT_DRAW_IMAGE: excalidraw/excalidraw:latest
-    KIT_DRAW_TRAEFIK_HOST: draw.kit.pivoine.art
-    KIT_FIGLET_IMAGE: ghcr.io/valknarness/figlet-ui:latest
-    KIT_FIGLET_TRAEFIK_HOST: figlet.kit.pivoine.art
     # Jellyfin
     JELLY_TRAEFIK_ENABLED: true
     JELLY_COMPOSE_PROJECT_NAME: jelly