* perf(server): bound Git process starts
Git refresh bursts could keep creating short-lived processes at the concurrency ceiling, causing sustained process churn on constrained hosts. Apply one daemon-global start-rate and concurrency policy to every Git command while preserving the legacy concurrency environment variable.
* build(nix): update npm dependency hash
* fix(server): hold Git slots until process exit
* fix(server): enforce Git limits across process lifetime
* fix(server): align Git metrics with process exit
* Fix Git limiter test deadlocks
* Tune default Git process rate
* feat(server): expose daemon Git pressure metrics
Separate limiter queue wait from Git execution time and report subscription ownership so accumulating work is visible in the existing runtime log.
* fix(server): collect subscriptions in agent metrics
Reuse the existing agent snapshot during runtime flushes so WebSocket shutdown does not require an additional AgentManager method call.
* test(server): retry transient hub cleanup
