Mac in the headset: measure every frame, adapt to the network, separate windows

- Per-frame timing on the Mac's clock (capture, encode, network, decode,
  draw), viewer clock sync and reports, input echo, /stats and a HUD.
- scripts/macview-bench.py: repeatable runs on the real Frame, a shaping
  relay (no sudo), interleaved A/B between agent settings; results in
  bench/results/.
- Adaptive controller: ack-based send gate with jitter-aware slack, AIMD
  bitrate that knows when a stream is app-limited, fps then size tiers.
  On a 50->3->50 Mbit/s step, scroll p95 went from 4.7 s to 72 ms; no cost
  on a clean link.
- Separate mode: real AppKit event loop (HiDPI and NSScreen now work),
  cropped capture for fixed-size windows, windows kept on their display,
  graceful quit restores windows; stop/start races fixed.
- Encoder timeline clamp (no oversized frame after a pause).
- Frame Control shows each live stream's fps, delay, bitrate and tier.

Reviewed by GPT-6 Astra xhigh (read-only), 7 rounds; findings fixed.

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

docs/how-the-frame-works.md

@@ -52,6 +52,7 @@ Lepton (Android 11, podman container "lepton-dev") ← its own panel, app 305600
 | Power actions need `sudo`, which asks for the Developer Mode password over SSH. | Frame Control's power buttons |
 | **SSH server:** OpenSSH 9.7p1. It offers `publickey,password` (keyboard-interactive is off, PAM on) and also asks `userdbctl ssh-authorized-keys` for keys. OpenSSH ≥ 8.8 rejects SHA-1 `ssh-rsa` signatures by default, so a client whose RSA support is SHA-1 only (the Swift library Citadel, for one) can't log in with the RSA key that devkit pairing installs; use ed25519 (**inferred** from OpenSSH defaults). **Verified 2026-09-27**, BUILD_ID 20260922.6101926. | [iphone.md](iphone.md), `ui/frame_connect.py` |
 | **A Chromium app window on gamescope's `:0` with its own `STEAM_GAME` becomes a panel, even when started over SSH.** `chromium-xr/chrome --ozone-platform=x11 --app=URL --window-size=1280,720` got a 1920×1080 window, and tagging it produced `[Overlays] Created: valve.steam.desktopgame.<id>` in `~/.local/share/Steam/logs/vrwebhelper_systemui.txt`. Chromium XR decoded a 1080p H.264 WebCodecs stream from the Mac at about 60 fps. XTest events sent to `:0` (libXtst through Python ctypes) did not reach the page. The Frame has `libXtst`, `xprop`, `xwininfo`, `curl` and the `C.utf8` locale. **Verified 2026-09-28**, BUILD_ID 20260925.6191901. | [mac-in-headset.md](mac-in-headset.md) |
+| **Streaming video into a panel: what the Frame adds.** Chromium XR decodes H.264 in **software** (1920×1290 at about 9 Mbit/s took 4–6 ms per frame); its GL is ANGLE → zink → Turnip on the Adreno 750, and it logs `GetVSyncParametersIfAvailable() failed`. An idle page's `requestAnimationFrame` runs at about 140 Hz; when the headset is worn or woken, SteamVR picks the 4320×2160 @ 144 Hz mode. **An unworn headset throttles panel apps** whatever they draw: a local canvas page ran at 58 fps for about 6 s, then 28, then about 15 once in standby (vrserver logs `entering standby`, with `power.pauseCompositorOnStandby 1`). `vrcmd --handlewakeup` gave 137–144 fps for about 2 s, then 36. So a panel's frame rate and compositor delay can only be measured while it's worn. `tailscaled` runs with `--tun=userspace-networking` and cost about 8% of a core at 9 Mbit/s (0.5% over the LAN address). Wi-Fi power saving is on (`iw … get power_save`). **Verified 2026-09-28**, BUILD_ID 20260925.6191901. | [mac-in-headset.md](mac-in-headset.md#measuring) |
 | **Tools on the image:** Python 3.12.3, `ffmpeg`, `openssl`, `curl`, `rsync`, `zip`/`unzip`, `flatpak`, `wpctl`, `podman`. **No `adb`.** `steamos` is uid 1000, in `wheel`, and sudoers has `%wheel ALL=(ALL) ALL`, so `sudo -S` takes the Developer Mode password on stdin. **Verified 2026-09-27.** | Running Frame Control's server on the Frame (`FRAME_LOCAL=1`, [iphone.md](iphone.md)) |
 | **Each Lepton instance is a podman container** named `lepton-steamlaunch-<instance id>`, labelled with its ADB port (`podman ps --format '{{.Names}} {{.Labels.adb_port}}'`). `podman exec <container> /system/bin/sh -c '…'` runs Android's shell inside it with no adb at all (used for `pidof` and `logcat` by the app tester). Running `wm size`/`wm density` that way is untested. **Verified 2026-09-27.** | `ui/frame_android.py`, the iPhone app's display settings |
 | **Asleep means off the network.** In standby the Frame stops answering on its LAN address, `frame.local` and Tailscale alike (`Host is down`, `No route to host`, timeouts), and ping fails. It was unreachable for about 2.5 hours until woken. Nothing over SSH can wake it. **Verified 2026-09-27.** | Frame Control's offline banner and retries |