25.8 Stable: Rebase CICD onto 25.8.15

[zvonand]

Changelog category (leave one):

• CI Fix or Improvement (changelog entry is not required)

CI/CD Options

Exclude tests:

• Fast test
• Integration Tests
• Stateless tests
• Stateful tests
• Performance tests
• All with ASAN
• All with TSAN
• All with MSAN
• All with UBSAN
• All with Coverage
• All with Aarch64
• All Regression
• Disable CI Cache

Regression jobs to run:

• Fast suites (mostly <1h)
• Aggregate Functions (2h)
• Alter (1.5h)
• Benchmark (30m)
• ClickHouse Keeper (1h)
• Iceberg (2h)
• LDAP (1h)
• Parquet (1.5h)
• RBAC (1.5h)
• SSL Server (1h)
• S3 (2h)
• Tiered Storage (2h)

[github-actions]

Workflow [PR], commit [17f5789]

[CarlosFelipeOR]

CI failures justification (rebase-only to 25.8.15)

The CI failures in this PR are already addressed or being addressed as part of the 25.8.15 rebase:

• S3/*/zero copy replication
  Regression in zero-copy replication introduced in 25.8.15.
  Issue Regression: S3 zero-copy replication leaves replica out of sync in 25.8.15 #1338 was opened and the fix was made upstream.
  Once it is backported, these regression tests will pass.

• /aggregate functions/part 1/uniqTheta
  Failure caused by an upstream bug fix that changed the expected result.
  Snapshots were already updated in Altinity/clickhouse-regression to reflect the correct behavior.
  Failure: RegressionTestsRelease /aggregate functions/part 1/uniqTheta - snapshot outdated clickhouse-regression#96
  After updating the commit hash, this test will pass.

• /iceberg/*/show tables queries and /iceberg/*/show data lake catalogs in system tables
  These tests are failing because this PR branch does not yet include the backports from PR 25.8.15 Stable backport of #88341, #89914 #1331.

Stateless tests

• 02887_mutations_subcolumns (Stateless tests, arm_binary, parallel)
  Known flaky test, not related to this PR. The test uses the deprecated Object(Nullable('json')) type which has inherent race conditions between metadata updates and query execution.
  A previous fix (ClickHouse#61198) reduced but didn't eliminate the flakiness. The test was eventually removed from upstream master as part of deprecating the Object type (commit c857429).