* fix(server): stop short start gates from undercutting provider startup budgets
Agent creation still failed on contended cold starts after #3578, because two
shorter gates on the same path fire before the event-stream readiness budget can
apply. A traced creation reached session.create twelve seconds in, past the 10s
session.create gate, and the agent was then killed by a bare "timeout" at fifteen
seconds from AGENT_RUN_START_TIMEOUT_MS while the SSE connect was still running.
A run-start bound of 15s wraps a path that is deliberately allowed 30s, so the
outer gate always wins and the inner budget is unreachable.
Give session.create the shared OPENCODE_SERVER_STARTUP_TIMEOUT_MS budget, since
creating the first session for a directory is part of OpenCode coming up, and
derive its error message from the constant instead of hardcoding "10s". Raise
AGENT_RUN_START_TIMEOUT_MS to 60s with a comment recording that it must stay
above the slowest provider startup budget; it stays a literal because that module
is provider-agnostic.
Related to #3571.
* test(server): drive the run start budget through a real AgentManager
The run start boundary tests replaced AgentManager.waitForAgentRunStart with a
bare timer, so they never exercised the production run-state transition or the
agent_state subscription the real wait depends on. That path could regress while
the tests stayed green.
Build the scenario on a real AgentManager with a provider session that holds its
turn start open for a configurable span, so pendingRun.started, the lifecycle
change to "running", and the agent_state notification are what the wait actually
observes. Budgets stay independent literals and the settled-before/after
assertions are unchanged.
* fix(server): describe agent run start timeouts
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Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>
