feat(webapp,database): opt-in per-client Prisma driver adapters

Add per-client env vars to route each Prisma client through @prisma/adapter-pg
(node-postgres) instead of the built-in engine driver. All default off, so
behavior is unchanged unless a flag is set:

- CONTROL_PLANE_DATABASE_WRITER_DRIVER_ADAPTER
- CONTROL_PLANE_DATABASE_REPLICA_DRIVER_ADAPTER
- RUN_OPS_DATABASE_WRITER_DRIVER_ADAPTER
- RUN_OPS_DATABASE_REPLICA_DRIVER_ADAPTER
- RUN_OPS_LEGACY_DATABASE_WRITER_DRIVER_ADAPTER
- RUN_OPS_LEGACY_DATABASE_REPLICA_DRIVER_ADAPTER

Enables the driverAdapters preview feature on both schemas (keeps the Rust
query engine; does not add queryCompiler). Each adapter pool is built with a
bounded connectionTimeoutMillis and an onPoolError handler.

Handle the connect-failure differences the adapter introduces:
- isInfrastructureError now recognizes the adapter's connect-failure shapes
  (P2010 'not reachable' and raw ECONNREFUSED/ENOTFOUND-class errors) so the DB
  host is still scrubbed from API-client errors and infra failures are logged.
- isPrismaRetriableError treats the adapter pool-acquire timeout as retriable,
  preserving the P2024 retry behavior.

refs TRI-13039

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ericallam

.server-changes/prisma-driver-adapter-per-client.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+Each database client can now optionally connect through the node-postgres driver, configurable independently per client and off by default, so default behavior is unchanged.