feat(webapp,database): opt-in per-client Prisma driver adapters (#4539)

## What

Adds an opt-in path to run each Prisma client through
**`@prisma/adapter-pg`** (the node-postgres driver) instead of the
built-in engine driver, controlled by a **per-client env var, all off by
default**:

| env var | client |
|---|---|
| `CONTROL_PLANE_DATABASE_WRITER_DRIVER_ADAPTER` | control-plane writer
|
| `CONTROL_PLANE_DATABASE_REPLICA_DRIVER_ADAPTER` | control-plane
replica |
| `RUN_OPS_DATABASE_WRITER_DRIVER_ADAPTER` | new run-ops writer |
| `RUN_OPS_DATABASE_REPLICA_DRIVER_ADAPTER` | new run-ops replica |
| `RUN_OPS_LEGACY_DATABASE_WRITER_DRIVER_ADAPTER` | legacy run-ops
writer |
| `RUN_OPS_LEGACY_DATABASE_REPLICA_DRIVER_ADAPTER` | legacy run-ops
replica |

With every flag unset the construction path is byte-identical to today
(`datasources` URL + Rust engine), so this is inert until a flag is
turned on. Per-client granularity allows enabling the adapter only where
it's wanted.

## How

- Enables the `driverAdapters` preview feature on both schemas
(`@trigger.dev/database` and `@internal/run-ops-database`). This keeps
the **Rust query engine** — it does NOT add `queryCompiler` — so query
behavior, result types, and engine tracing spans are unchanged.
- A shared `buildDriverAdapterPool` builds each client's `pg.Pool` with
an explicit `max`, a bounded `connectionTimeoutMillis` (the
node-postgres pool otherwise waits unbounded on acquire), and an
`onPoolError` handler (an unhandled idle-connection error would
otherwise crash the process). Threaded through all four client builders
via a `useDriverAdapter` flag.
- Adds `@prisma/adapter-pg` + `@types/pg` to the webapp; `pg` is already
pinned at `8.15.6` (adapter-pg 6.x requires `pg < 8.17`).

## Connect-failure handling (the important correctness/security bit)

Under the adapter an unreachable DB no longer surfaces as
`PrismaClientInitializationError` / `P1001`; it becomes a `P2010`
"Database not reachable: <host>" (or a raw
`ECONNREFUSED`/`ENOTFOUND`-class error). Two handlers are updated so a
client on the adapter behaves like today:

- **`isInfrastructureError`** now recognizes those shapes (P2010 with a
connectivity message, and raw connectivity errno codes). Without this,
the DB **hostname would leak into API-client-facing errors** and the
failure would go unlogged. Security-relevant.
- **`isPrismaRetriableError`** treats the adapter's pool-acquire timeout
("timeout exceeded when trying to connect") as retriable, preserving the
`P2024` retry behavior the adapter otherwise drops.

## Evidence

Validated on an isolated stack that mirrors the production DB topology
(chained PgBouncers in front of writer + reader):

- **Behavioral parity:** raw-query results and Prisma error codes/`meta`
are byte-identical between the engine driver and the adapter across the
queried shapes (unique-constraint `meta.target`, record-not-found,
transaction-timeout, serialization-failure, etc.).
- **Feature matrix:** a full 380-project queue-ay pass shows no
adapter-caused regressions — pass/fail parity between adapter-off and
adapter-on, with the residual failures being pre-existing
known-failures/flakes common to both.

## Rollout / rollback

All flags default off; enable per client via env var, roll back by
unsetting and redeploying (no data migration). Recommended first target
is a single writer; enable one client at a time.

## Follow-ups (not in this PR)

- `$metrics`-based pool observability is removed under the adapter (the
Prometheus route + `db.pool.connections.*` instruments); the metrics
replacement (via `pg.Pool` counters) lands in a separate PR.
- Note for operators: on the adapter path, interactive-transaction
`maxWait` does not bound pool acquisition — `connectionTimeoutMillis`
does.

## Note on connection-string parameters

The adapter pool is built from the base DSN, so Prisma-specific DSN
parameters that node-postgres does not understand are not honored when a
client is on the adapter:

- **Prisma TLS spellings** (`sslaccept`, `sslcert`, etc.) —
node-postgres uses `sslmode`/`ssl` instead. Our production DSNs do not
use these Prisma-specific TLS params, but any deployment whose DSN
relies on them must be checked before enabling a flag.
- `pgbouncer=true` and `statement_cache_size` — effectively moot under
the adapter, which uses no persistent named prepared statements.

`connection_limit`, `pool_timeout`, and `schema` are handled explicitly
(passed as `max`/`connectionTimeoutMillis` and PrismaPg's `{schema}`
option).

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
+---
+
+Groundwork for an alternative database connection driver, gated behind configuration and disabled by default, so there is no change to default behavior.