Steam Frame from a Mac: research docs and helper scripts

README with the minimum-typing checklist (Developer Mode toggle + Set User
Password; the rest runs from the Mac), docs for SSH, streaming, file
transfer, and open questions with sourced confidence levels, plus Mac-side
zsh helpers and a fallback headset bootstrap.

Scripts are UNTESTED against hardware: checked with zsh -n / bash -n /
shellcheck only. Two SWE-2 Max read-only review passes (devin -p --model
swe-2-max); verified findings fixed.

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

scripts/bootstrap-on-frame.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# Runs ON the Steam Frame (fallback path only; normally Developer Mode's
+# toggle + "Set User Password" is enough and this is not needed).
+# Served by scripts/serve-bootstrap.sh, which substitutes the public key.
+#
+# UNTESTED against real hardware. Idempotent.
+set -eu
+
+KEY='__PUBKEY__'
+
+mkdir -p "$HOME/.ssh"
+chmod 700 "$HOME/.ssh"
+touch "$HOME/.ssh/authorized_keys"
+chmod 600 "$HOME/.ssh/authorized_keys"
+if grep -qxF "$KEY" "$HOME/.ssh/authorized_keys"; then
+  echo "key already present"
+else
+  echo "$KEY" >> "$HOME/.ssh/authorized_keys"
+  echo "key added"
+fi
+
+echo "Enabling sshd. If sudo asks for a password you never set, press Ctrl-C,"
+echo "set one in Steam Settings > Developer > Set User Password (or run: passwd),"
+echo "then re-run the same one-liner."
+sudo systemctl enable --now sshd
+
+echo
+echo "sshd: $(systemctl is-active sshd)   user: $(id -un)   host: $(hostname)"
+ip -4 -brief addr show scope global 2>/dev/null || true
+echo "Now on the Mac: scripts/connect.sh"