Ran the following commands on librarian version 0.31.1:

```
go install github.com/googleapis/librarian/cmd/librarian@0.31..1
librarian install nodejs
librarian generate --all 
```

## Description

Upgrade all generated packages to Node 22 along with their dependencies.

For all `package.json` files inside `packages/**` folder we set "node":
">=22" for `engines`. We also make sure that for all of these
`package.json` files the dependencies that match the core libraries are
all on the latest version so that all core library dependencies
correspond to node v22.

Note that a branch update is likely required to get the zizmor checks to
pass.

Also note that upgrading the auth library dependencies causes compiler
errors so we opt out of upgrading the auth library.

## Impact

Encourages customers to adopt new Node version which avoids issues due
to lack of Node 18 support.

## Next Steps

Upgrade the auth dependencies that we chose not to upgrade this time due
to the compiler error. Tracked
[here](https://b.corp.google.com/issues/541318013).

Now that we've migrated to librarian for new API libraries, this can go
away.

…pis#9030)

While trying to get the [handwritten split project](googleapis#8934) finished, I ran into a lot of resource leaks in the bigtable system tests. These ended up being extensive enough changes that I moved them to their own PR (this one).

…googleapis#9023)

## Summary
This PR implements the core `Client`, `Pool`, and `Query` execution
interfaces for `@google-cloud/spanner-driver`, providing compatibility
with `node-postgres` (`pg`) driver layer for Google Cloud Spanner

---

## Key Changes

### 1. `Client` Connection & Execution Queue (`src/lib/client.ts`)
- **`Client` Class**: Implements `node-postgres` compatible `Client`
handle managing connection state (`isConnected`), transaction status
tracking (`txStatus: 'I' | 'T' | 'E'`), and DSN resolution.
- **Sequential Task Queue (`queryQueue`)**: Enforces sequential query
execution order per client connection handle.
- **Transaction Status Lifecycle**: Updates `txStatus = 'I'` only after
statement execution completes (`COMMIT`, `ROLLBACK`, `ABORT`).
- **`release()` Method**: Added `client.release()` method delegating to
connection teardown for `node-postgres` compatibility.
- **Unhandled Error Prevention**: Added `query.listenerCount('error') >
0` check prior to emitting `'error'` events, preventing Node process
crashes when queries are consumed via Promises (`await client.query()`).

### 2. `Query` Class & Thenable / EventEmitter Integration
(`src/lib/query.ts`)
- **Dual Invocation Model**: Extends `EventEmitter` for row streaming
(`.on('row', cb)`, `.on('end', cb)`) while implementing the Thenable
interface (`then`, `catch`, `finally`) for `async`/`await` support.
- **Overload Support**: Supports query strings, `QueryConfig` objects,
`Query` instances, positional value arrays (`$1`, `$2`), and Node
callbacks (`(err, res) => void`).
- **Constructor Robustness**:
- Added `text !== null` guard when initializing from objects (`typeof
text === 'object' && text !== null`).
- Added support for overriding positional `values` and `callback` when
instantiating from an existing `Query` instance.

### 3. `Pool` Scaffolding & Callback Single-Invocation Rule
(`src/lib/pool.ts`)
- **`Pool` Class**: Implements `connect()`, `query()`, and `end()`.
- **Client Binding**: Binds `client.release = client.end.bind(client)`
during client acquisition with `TODO(PR 4 - Connection Pooling)` markers
for pool recycling in PR 4.
- **Single Invocation Guarantee**: Isolated `_doConnect()` connection
acquisition error handling from query execution, ensuring connection
failures call callbacks exactly once without hanging or double
callbacks.
- **3rd-Argument Callback Overload Resolution**: Resolved 3rd-argument
callback parameters when executing `pool.query(query, values, callback)`
or `client.query(query, values, callback)`.

… for retry failures

- Unify formatting of Errors and objects under a single block inside
formatRetryError to reduce code duplication.
- Ensure standard errors, GaxiosErrors, and custom errors with
empty/missing properties are correctly formatted.