try to avoid some locking

[zzstoatzz]

[wip] reduce SQLite locking

not sure about this yet, just looking for now

for example: i saw that worker heartbeats could trigger "database is locked" errors when using SQLite, which seems related to serialization during work pool status transitions.

this pr

• updates work pool status transition in worker_heartbeat by only acquiring lock when needed
• adds with_for_update=True in a flow run read and a work pool query to ensure atomic operations (TODO revisit)

an assumption im making is that we only need to serialize access when actually changing a work pool's status from NOT_READY to READY - the worker heartbeat upsert itself uses on_conflict_do_update

(maybe) consider logfire for exploring bottlenecks

i am not suggesting i commit this optional logfire instrumentation as is, though would be open to putting it behind a real flag if we eventually had buy in

related to #16299

[codspeed-hq]

CodSpeed Performance Report

Merging #17566 will not alter performance

_{Comparing perf (5c386bf) with main (007ef06)}

Summary

✅ 2 untouched benchmarks