Fix installed service and launcher paths; wait for the pointer helper

The service and menu-entry templates still pointed at the old frametop/
subfolder, so the pointer helper, input relay, and settings apps couldn't
start after a clean install. The pointer helper's install step also failed
when the service was still starting after 3 s; it now waits up to 20 s and
doesn't abort the installer.

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

input/frametop-input-relay.service

@@ -1,7 +1,7 @@
 # Template: the installer replaces @REPO@ with the repo path on the Frame.
 [Unit]
 Description=Frametop input relay: stable virtual mouse and keyboard for SteamVR
-Documentation=file://@REPO@/frametop/README.md
+Documentation=file://@REPO@/README.md
 # SteamVR opens input devices only at startup, so the virtual devices must exist first.
 Before=steamvr.service
 
@@ -9,7 +9,7 @@ Before=steamvr.service
 # READY=1 is sent only after the virtual devices exist.
 Type=notify
 NotifyAccess=main
-ExecStart=/usr/bin/python3 @REPO@/frametop/input/input-relay.py
+ExecStart=/usr/bin/python3 @REPO@/input/input-relay.py
 Restart=on-failure
 RestartSec=1
 # systemd holds the virtual devices' file descriptors across relay restarts,