feat(gui): right_arm.js — auto-refresh, detect, move, home, custom

src/presa_mano/main.py

@@ -107,7 +107,7 @@ def index() -> HTMLResponse:
     idx = WEB_DIR / "index.html"
     html = idx.read_text(encoding="utf-8")
     # Cache-bust app.js and style.css with their mtime so a rebuild forces refetch.
-    for name in ("app.js", "work_plane.js", "style.css"):
+    for name in ("app.js", "work_plane.js", "right_arm.js", "style.css"):
         f = WEB_DIR / name
         if f.exists():
             v = int(f.stat().st_mtime)