feat: add figlet tool to kit stack

Added figlet-ui service to kit stack:
- Image: ghcr.io/valknarness/figlet-ui:latest
- Host: figlet.kit.pivoine.art
- Traefik routing with HTTPS and compression
- Watchtower auto-update enabled

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

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

arty.yml

@@ -142,6 +142,8 @@ envs:
     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