The README now answers the question a migrator actually has: what do I delete,
and what covers it afterwards.
* a new "Replacing androidtv / androidtv_remote + the glue" section: the
back-up → remove-the-platform-YAML → remove-mediasession2mqtt → delete the old
integrations → add this one → update automations checklist, plus a table
mapping every retired piece to what serves it now. It notes that Wholphin
publishes no MediaSession of its own and gets its now-playing from the ADB
media session, so no bridge is needed for it either;
* the setup steps describe the real flow (name + one address, both transports on
by default, ADB pairing then PIN pairing, each with a skip);
* the YAML seed section carries a complete, copy-pasteable block. It documents
ONLY the keys `_yaml_seed_blocks` honours (name, host, adb_port, adb_enabled,
and the still-accepted protocol_host/adb_host) and says explicitly that the
rest lives on the Configure page — an example that lists ignored keys is worse
than no example;
* the state-ladder section, the discovery bullet and the options list follow the
two-transport, one-address reality.
`tests/test_readme.py` pins the doc/code contract: the example's keys are a
subset of what the seed reads, the example uses the current `host` key, and the
guide keeps naming the retired integrations and glues.
Verified: 326 passed / 2 skipped, ruff clean.
