Document how the host emulator is driven over adb from the agent
container: the start script now boots headless by default and trusts
remote adb keys via ADB_VENDOR_KEYS at launch, since the TV system
image is a user build that blocks pushing keys to adb_keys after boot.
AGENTS.md points to the new doc and fixes the stale SDK path.
On launch and on every destination switch the first card of the
content gets focus automatically - invisible focus on chrome confused
'Do I need to press DOWN first?'. The search button shows a white ring
when focused, and the top bar gained a real account button (person
icon + logged-in username) replacing the cryptic monitor icon.
start-emulator.sh: headless-safe boot (no -gpuhost crash without a
display), whitelists adb public keys headlessly (drop them into
/tmp/jtube-adbkeys/), and starts the socat bridge itself.
scrcpy cannot talk to headless emulators inside the container: the
AOSP ATD image lacks framework pieces (KeyCharacterMap NPE) and there
is no GPU/KVM in the container at all. The script boots the android-tv
image image on the host with -gpu host and a window (so the RSA dialog
is clickable), installs the current debug APK and leaves the app
running; the container's socat bridge then exposes it as
rutherford:5556 for adb/scrcpy from anywhere.
