* feat(conventions): standard schema models + effective-map merge
* feat(orchestrator): park provider on persistent server overload (529/500)
A 429 rate limit already parks a provider — queue its spawns, probe until it
recovers — but a persistent 529/500/503 overload had no such break: the run
died and the orchestrator crash-retried straight back into the overload,
burning tokens in a respawn loop.
Generalize the park to provider-unavailability. On a non-graceful Anthropic
agent exit, match the API's overload markers (overloaded_error /
internal_server_error / "API Error: 5xx") against the dead container's own
output and park the provider with kind="overloaded"; the existing spawn gate
already queues any parked provider, and the probe-resume loop revives the task
when it recovers. Grok keeps its exit-75 path; both now route through one
_park_provider_unavailable helper. Markers are kept specific so an agent that
merely writes about HTTP 500/529 can't trip the break.
Fix the recovery probe to require a 2xx: it treated any non-429 as recovered,
so a probe that itself got a 529 would have resumed agents straight back into
the overload — wrong for the new path and for a 429 that lifts into a 5xx.
Gated by ROBOCO_OVERLOAD_BREAK_ENABLED (default on; off => crash-retry).
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Co-authored-by: Renn F <rennf93@users.noreply.github.com>
