## Description
Reuses the reconciliation lock transaction for read operations during
prebuilds reconciliation, reducing unnecessary database connections.
## Changes
* Use the lock transaction (`db`) for read operations and `c.store` for
write operations:
* `GetPrebuildsSettings`: now uses `db`
* `SnapshotState`: now uses `db`
* `MembershipReconciler`: continues to use `c.store` (performs write
operations)
* Add comments explaining the transaction model and when to use `db` vs
`c.store`
Related to: https://github.com/coder/coder/pull/20587
Susana Ferreira
000bc334c9