Backport of 'Fix ci_finished_builds engine swap on deferred post-deploy' into 18.11

What does this MR do and why?

Backports !240219 (merged), !240627 (merged), and !240798 (merged) (merged commit b4f205d5) to 18-11-stable-ee.

ClickHouse post-deployment migration 20260108073937_alter_ci_finished_builds_engine_with_version failed in three ways on stable branches that run ClickHouse 23.x/24.x:

1. Structure mismatch (#593129 (closed)): Code: 122. DB::Exception: Tables have different structure. (INCOMPATIBLE_COLUMNS) when self-managed customers upgrade from 18.8.x to 18.9.x–19.0.x. Root cause: hardcoded CREATE TABLE for the tmp table; later-timestamped migrations add columns/projections before this post-deploy migration runs. Fixed in master by !240219 (merged).

2. Missing PARTITION BY / ORDER BY on CH 23.x/24.x: Code: 36 BAD_ARGUMENTS because the CREATE TABLE … AS source ENGINE = … form does not implicitly inherit those from the source on older ClickHouse. Fixed in master by !240627 (merged) (specified explicitly).

3. drop_tmp_table UNKNOWN_SETTING on CH 23.x: SETTINGS max_table_size_to_drop = 0 is only valid as a query-level setting on CH 24.0+; on CH 23.x it raises Code: 115 UNKNOWN_SETTING. Worse, simply omitting it would fail DROP for any customer with >50 GB in tmp. Fixed in master by !240798 (merged): on CH 23.x DETACH every partition first (size check does not apply), then DROP the empty table.

This branch contains three cherry-picks from master:

commit	from MR	purpose
ca503ffb	!240219 (merged)	Initial fix: clone source structure via CREATE TABLE … AS source
d811b49f	!240627 (merged)	Explicit PARTITION BY / ORDER BY for CH 23.x/24.x compatibility
b4f205d5	!240798 (merged)	DETACH+DROP for CH 23.x, version-agnostic spec, dedup-gate threshold corrected to CH 24.8+, self-healing create_tmp_table, and a .pluck('name') rubocop fix for rubocop-rails 2.26+.

Verified end-to-end on CH 23.11.3, 24.9.1 and 25.x via docker — full migration sequence succeeds; row count preserved; engine swapped from ReplacingMergeTree(deleted) to ReplacingMergeTree(version, deleted).

References

• Issue: #593129 (closed) (severity::2, priority::2, Customer Interest, GitLab Dedicated)
• Master MRs: !240219 (merged), !240627 (merged), !240798 (merged)
• Customer ticket: ZD#700951

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