v0.2.13

• DECIDE_LOCAL_ONLY=1, or local_only=True, refuses every backend that sends the state to a server. from_env stops adding hosted backends whose keys happen to be in the environment, naming one in DECIDE_BACKENDS raises ConfigError, and so does passing one to Client(...), since the check reads each backend's Capabilities.local. One environment variable makes a deployment local only, instead of every call site having to be written that way.
• docs/gating.md says what a single-backend chain does when its answer misses the gate: there is no next backend, so the answer is accepted or raised, never escalated.