Document the Frame's recovery images and what we learnt about the device

- docs/recovery-and-images.md: where Valve's Frame images are (not linked from
  the SteamOS download page), file names, sizes and our checksums, the GPT
  layout with exact start sectors, what's in rootfs-A (btrfs, SteamOS 0.3.0
  build 20260922.5152327, users, sudo and sshd config), extracting it, running
  it without the headset, and Valve/Collabora's Holo Core aarch64 preview.
- how-the-frame-works.md: correct the recovery image file names; add verified
  facts on the SSH server, tools on the image (no adb), Lepton instances as
  podman containers, going off the network when asleep, and the battery
  reading at full charge.
- ssh.md: pairing from an iPhone and why devkit RSA pairing doesn't fit it.
- open-questions.md, README.md and the steam-frame skill point to the new pages.

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

.claude/skills/steam-frame/SKILL.md

@@ -27,6 +27,9 @@ desktop or panels.
 | Flatpaks | `docs/streaming.md` | `scripts/install-apps.sh` |
 | Launch an app inside the desktop panel | the script's header comment | `scripts/run-on-frame.sh` |
 | Mac GUI over all of this | `README.md` → Frame Control | `scripts/frame-ui.sh` |
+| iPhone/iPad app (server runs on the Frame, `FRAME_LOCAL=1`) | `docs/iphone.md` | `ios/`, `ui/local-bin/ssh` |
+| Recovery images, factory reset, boot loops | `docs/recovery-and-images.md`, `docs/how-the-frame-works.md` | `~/Downloads/steam-frame-recovery/` |
+| Test without the headset (the Frame OS image's own sshd) | `tests/frame-container/README.md` | `tests/frame-container/frame-image.sh` |
 | What's still unverified | `docs/open-questions.md` | — |
 
 Each script's usage is in its header comment. Read the header rather than