[BUG]: WebKit browser tests fail intermittently in CI

**Describe the bug**

The WebKit browser test suite intermittently fails in GitHub Actions across unrelated PRs and on `main`. The failing Node version and test file vary between runs, while the Chromium and Firefox suites usually pass.

The failures I have seen are in `webkit-memory.test.web.js` and `webkit-idb.test.web.js`, with errors such as:

```
page.evaluate: RuntimeError: Out of bounds memory access
```

```
INITDB failed to initialize: child process was terminated by signal 1: Hangup
```

```
RuntimeError: call_indirect to a null table entry
```

**To Reproduce**

I do not have a reliable local reproduction. Running the repository's "Build and test PGlite packages" workflow eventually hits it.

Some examples from unrelated changes:

- PR #1079, Node 21 and 22: https://github.com/electric-sql/pglite/actions/runs/32092403347
- PR #1081, Node 24: https://github.com/electric-sql/pglite/actions/runs/32089886034
- The next run completed successfully: https://github.com/electric-sql/pglite/actions/runs/32090752581
- PR #1073, Node 22: https://github.com/electric-sql/pglite/actions/runs/30863936008
- PR #1067, Node 23: https://github.com/electric-sql/pglite/actions/runs/30149767473
- PR #1066, Node 23: https://github.com/electric-sql/pglite/actions/runs/29791702977
- PR #1060, Node 20: https://github.com/electric-sql/pglite/actions/runs/29666399267
- `main`, Node 24: https://github.com/electric-sql/pglite/actions/runs/30364466212

**Logs**

In the PR #1079 run, the OPFS-AHP tests passed before the failures occurred in the WebKit memory/IDB tests. The same pattern appears in unrelated runs: the failure is isolated to WebKit and moves between Node matrix entries and storage targets.

**Details**

- Environment: GitHub-hosted Ubuntu runners
- Node versions observed: 20.x through 24.x
- Test runner: the repository's current Vitest/Playwright setup
- Browser target: WebKit
- Reproduction locally: not reproduced so far

**Additional context**

This looks like a pre-existing flaky WebKit/initdb lifecycle issue rather than a failure tied to a specific PR. It would be useful to identify the first failing lifecycle boundary and add enough diagnostics to distinguish an initdb child-process shutdown from a WebAssembly runtime failure.

Start with the “Build and test PGlite packages” GitHub Actions workflow and compare its WebKit matrix failures in webkit-memory.test.web.js and webkit-idb.test.web.js. Trace the lifecycle around the reported initdb and WebAssembly errors, using the linked runs as failure examples. Done means diagnostics identify whether each failure begins with child-process shutdown or WebAssembly runtime failure.

Written by the indexing model from the issue text.