Improve movement ribbon layout with collision-aware labels and hover highlight.

Add FAC operator cheat sheet and link it from README and setup docs.

README.md

@@ -7,6 +7,7 @@ Interactive virtual art gallery: zoomable historical timeline with era click-to-
 | Document | Purpose |
 |----------|---------|
 | [Documentation/basics.md](Documentation/basics.md) | Architecture, layout, user flow |
+| [Documentation/FAC.md](Documentation/FAC.md) | **Command cheat sheet** — start/stop, import, deploy |
 | [Documentation/environments.md](Documentation/environments.md) | Dev/prod URLs, DB split, deploy, sync |
 | [Documentation/setup.md](Documentation/setup.md) | Install, env, npm scripts |
 | [Documentation/DB_structure.md](Documentation/DB_structure.md) | PostgreSQL tables |