Add reconciliation details to sk membership change rfc

[arssher]

Problem

RFC pointed out the need of reconciliation, but wasn't detailed how it can be done.

Summary of changes

Add these details.

[github-actions]

7403 tests run: 7049 passed, 1 failed, 353 skipped (full report)

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Failures on Postgres 15

• test_metrics_normal_work: release-arm64-with-lfc

# Run all failed tests locally:
scripts/pytest -vv -n $(nproc) -k "test_metrics_normal_work[release-pg15]"

Flaky tests (10)

Postgres 17

• test_pgdata_import_smoke[None-1024-RelBlockSize.MULTIPLE_RELATION_SEGMENTS]: debug-x86-64-without-lfc, release-arm64-without-lfc, release-arm64-with-lfc
• test_pgdata_import_smoke[8-1024-RelBlockSize.MULTIPLE_RELATION_SEGMENTS]: release-arm64-with-lfc, debug-x86-64-without-lfc, release-arm64-without-lfc
• test_metrics_normal_work: release-x86-64-without-lfc

Postgres 16

• test_metrics_normal_work: release-x86-64-with-lfc
• test_pull_timeline_while_evicted: release-x86-64-with-lfc

Postgres 14

• test_metrics_normal_work: release-x86-64-with-lfc

Test coverage report is not available

_{The comment gets automatically updated with the latest test results
8056b7b at 2025-01-28T05:44:29.693Z :recycle:}

[arpad-m]

the open questions I had are clear to me and I think it can be implemented this way.