Verify against a real Frame; switch clipboard to Klipper

The headset desktop is nested Plasma in gamescope with no wl-copy/xclip,
so paste-to-frame.sh now calls Klipper over plasmashell's D-Bus bus.
connect.sh, push.sh, paste-to-frame.sh and install-apps.sh were exercised
on SteamOS 0.3.0 (build 20260922); docs record what was confirmed.
Cross-provider review skipped at Alex's request (Astra quota exhausted).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

scripts/install-apps.sh

@@ -2,7 +2,9 @@
 # Mac-side: install Flatpaks on the Steam Frame over SSH (per-user, so they
 # survive SteamOS updates and need no sudo / steamos-readonly changes).
 #
-# UNTESTED against real hardware. Idempotent.
+# Verified on a Frame 2026-09-25 (remmina + --vnc-host). Idempotent.
+# The "exports/share is not in the search path" warning only applies to the
+# SSH shell; the headset desktop's XDG_DATA_DIRS already includes it.
 #
 # Usage:
 #   scripts/install-apps.sh remmina [--vnc-host my-mac.local]