Live view: a Desktop view that stays still, and Control to tap on the Frame (#46)

* Live view: a Desktop view that stays still, and Control to tap on the Frame

The live view gets a second source and a way to use the Frame from it:

- Desktop: the app panel in use in the headset, streamed from its own window
  (x11grab of gamescope's redirected window), so it doesn't move as the
  wearer looks around. A picker shows any other panel, view only.
- Control: on the Desktop view a tap or click lands exactly where you put it;
  drag is a mouse drag, press and hold right-clicks, two fingers scroll, and
  on a computer the mouse, wheel and keyboard work directly. On the headset
  view the view is a trackpad. A text field and key row type from a phone.

Input goes through gamescope's own EIS socket (the way Steam feeds Remote
Play input) with the libei already on the image: ui/frame_touch.py, over
the same long-lived ssh machinery as the keyboard agent, nothing to
install. It reaches the panel that has focus on either X display, which
the KDE Connect route can't. Verified on the Frame and from the iPhone app
in the Simulator.

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

* Control: fixes from review

- Keys held on the Frame are released with buttons when Control stops or
  the view loses focus; keys for the Frame no longer trigger Frame Control's
  own shortcuts.
- Taps only act when the picture on screen is the panel in use; positions,
  presses, keys, text and scrolls name their panel (display and window: ids
  repeat across :0 and :1, told apart by pid), and the Frame drops them if
  focus has moved on. Releases always go.
- While connecting, a tap keeps its position; on an error only releases wait
  and retries back off; trimming a long queue never drops a release.
- Lifting one of two scrolling fingers ends the scroll; a cancelled touch
  isn't a tap; clicks and holds on the bars around the picture do nothing.
- A capture loop from before a Live restart can't stop the new video.

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

* Control: close the targeting gaps from the second review

- The focused panel's display comes from GAMESCOPE_FOCUS_DISPLAY (gamescope
  packs ":1" into the first value), so a window id repeated across :0 and :1
  can't be mistaken; the pid is only the fallback.
- Presses, keys, text and scrolls read focus afresh on the Frame; only moves
  use a reading up to a second old.
- A gesture remembers the panel it started on and does nothing more if that
  stops being the one in use; a press with no panel to aim at isn't sent.
- Opening a screenshot clears the panel Control would act on; switching to
  another app releases held keys and buttons.
- Trimming keeps a click with its position; the error backoff holds for new
  input too.

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

* Control: fixes from the SWE-2 Max review

- The Frame side tracks keys as well as buttons and lets go of both when the
  session ends.
- A stale tap tells the page, which re-reads the panels at once.
- A paused input device waits instead of ending the session; only a
  disconnect does. An OS error on one event skips it.
- Presses check focus with two property reads and do the full lookup only
  when it changed.
- Writes to an agent's stdin are serialized, so two devices sending at once
  can't tear a line (the keyboard agent too).
- Connecting gives up with a message after 15 s instead of hanging on
  "Connecting…"; text goes in 100-character pieces so releases don't wait
  behind a long paste; a cancelled mouse gesture releases what's held.

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

* Control: stale clears, pauses reconverge, pastes split per request

- The Frame says it has caught up as soon as an aimed event lands after a
  stale one, so the page stops re-reading the panels.
- After a device pause it lets go of everything it holds (releases that
  arrived while paused were dropped), and waits for the device once per
  batch, not once per event.
- The quick focus check no longer freshens the panel geometry's age.
- Each request carries at most about 100 characters of text.
- Turning Control off while it connects doesn't report an error.

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

* frame_touch: build the socket path on the Frame, so Windows can import it for tests

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

* frame_touch: any event that goes through clears the stale flag

A trackpad move names no panel, so waiting for an aimed event could leave
the page re-reading panels for the rest of the session; a release still
aimed at the old panel doesn't count.

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

---------

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

README.md

@@ -35,8 +35,8 @@ See what the headset sees, install games and Android apps, move files and text a
 <tr>
 <td width="50%" valign="top">
 
-**👓 Headset view**<br>
-Live video of what the lenses show (about 30 fps), or a still of both eyes. Zoom, pan, full screen, save as PNG.
+**👓 Headset view and Desktop**<br>
+Live video of what the lenses show, or of the app panel in use, flat and still however the wearer looks around. Turn on Control and tap or click right on it to use the Frame from your phone or computer.
 
 </td>
 <td width="50%" valign="top">