Remove leftovers before a release

- gaze/tracker/lab/eyes_track.py: nothing used it
- Input Settings: the pointer role backend, whose page was removed
- ft-screens: no log line for every floating-window resize
- hands: ft-hands --help gives the palm-down default (1: off), the
  uninstall removes ft-handsctl's link, .frame-job is ignored
- Display Settings: "Save as profile…", not "Save current arrangement"
- two stale comments (ft-pointer's grabprobe, ft-gaze)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pointer/helper/ft-pointer.cpp

@@ -1139,8 +1139,8 @@ int main() {
         return "";
     };
 
-    // Spike: aim down from the panel's bottom edge, 1 cm a step, and log where SteamVR's
-    // laser hits something (the hit dot shows) and whether the window controls are up.
+    // grabprobe (maintenance): aim down from the panel's bottom edge, 1 cm a step, and log where
+    // SteamVR's laser hits something (the hit dot shows) and whether the window controls are up.
     auto grabProbe = [&](const char *key) {
         Panel p;
         Vec3 eye;