Add the distributed-aware state contributor rule: any feature that
keeps runtime state must choose shared (syncstate), single-runner
(advisorylock), stateless, or documented per-instance behaviour, so it
behaves correctly across multiple frontends instead of diverging
silently. Also sweeps the failover/localai-proxy docs for gaps found
along the way: the UI (chain editor field, health strip, overview
page, chain badge), the 429->ResourceExhausted trip and 501->skip
mappings, and a spec correction for the live-transcription bridge's
actual close behavior.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>