pg waldump improvements

[dimitri]

1. add neon resource manager in waldump
2. print end lsn

Only applies starting at Postgres 16, before that the pg_waldump and custom WAL Resource Managers are not ready.

Problem

Summary of changes

[github-actions]

If this PR added a GUC in the Postgres fork or neon extension,
please regenerate the Postgres settings in the cloud repo:

make NEON_WORKDIR=path/to/neon/checkout \
  -C goapp/internal/shareddomain/postgres generate

If you're an external contributor, a Neon employee will assist in
making sure this step is done.

[github-actions]

9119 tests run: 8465 passed, 0 failed, 654 skipped (full report)

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Code coverage* (full report)

• functions: 34.7% (8840 of 25482 functions)
• lines: 45.7% (71632 of 156719 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
1ff3d0c at 2025-08-01T16:05:41.137Z :recycle:}