Simplify export-system-logs article

[BorisTyshkevich]

Follow-up to #189. The article read like an investigation writeup rather than a KB page.

3313 words → 1278. For context, the median article in altinity-kb-setup-and-maintenance is 498 words and the previous longest was 1049 — #189 landed at 3× the section's longest.

What was cut

The removed material was ClickHouse internals that don't help someone configuring an export:

• The flush-mechanism walkthrough — SystemLogQueue::pop(), result.logs.swap(queue), queue->confirm() — replaced by the only part an operator acts on: a failed flush is not retried, so those rows are gone.
• Both C++ stack traces.
• The push-time vs sink-construction analysis. The usable rule is "an S3 target failure loses local rows, a URL target failure doesn't" — the reader doesn't need to know why.
• A 4-row measurement table justifying the data-loss finding, collapsed to one sentence carrying the same numbers (20/20, 1/20, 0/10).
• The reconciliation / Distributed-sender section — design prose that made no tested claim.
• The separate References list, merged into Related resources.

What was kept

Every tested recipe, unchanged in substance: the S3 export (with the settings-placement warning, which is the article's most practically valuable part), session log, URL, File, the direct external engine, the monitoring query, the post-upgrade dependency check, and the version table.

Verification

The DDL was reflowed onto fewer lines, so it was re-tested rather than assumed. All four SQL blocks were extracted from the article and executed verbatim on 26.7.5.10 against MinIO, followed by the glob read-back, monitoring and upgrade-check queries. Object sequence (query-log.ndjson, .1, .2, ...), all three session event types including LoginFailure, the appending file target, and the dependency output all match what the article claims. SystemLogErrorOnFlush stayed empty throughout.

Hugo build (0.128.2, CI-pinned): 328 pages, no shortcode leakage, anchor and both internal links resolve.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AsB1E5eSBXpaZT4jGzY57L

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