Persist the v4 plugin runtime state so recreating the runtime container no
longer discards installed plugins' artifacts, dependency environments and
installation-private data, and stop a transient Runner registry miss during
steering from dropping the message.
- docker-compose: bind-mount ./data/plugin-runtime for the plugin runtime
alongside ./data/plugins.
- kubernetes: add the langbot-plugin-runtime-state claim (5Gi) mounted at
/app/data/plugin-runtime, kept separate from the plugin data claim so
runtime state does not land inside the plugin directory.
- chat handler: treat RunnerNotFoundError while claiming steering as
"steering unavailable" and continue with a normal run; every other error
keeps propagating. The runner error imports move to module scope, which
the new early reference requires.
- tests: cover the steering fallback, the claimed-steering interrupt, and
the lasting-gap path that still reports runner-not-found.
The steering fallback buys one extra uncached registry lookup while a
runtime reconnects; it does not recover a gap that outlasts the message.
Martin