Note

Medium Risk
Changes the default async_insert behavior to enabled, which can alter INSERT latency/flush semantics and surface edge cases in clients and tests. Remaining code changes are mostly logging and test/config adjustments to force synchronous inserts where needed.

Overview
Enables async_insert by default by flipping the default in Settings and recording the behavior change in SettingsChangesHistory (26.2), with updated settings baseline expectations.

Updates AsynchronousInsertQueue to use the newer InterpreterInsertQuery::getSampleBlock signature and improves async-insert diagnostics by logging the batch’s source query_ids (and reducing reliance on the full query string) for queueing, flushing, and parse errors.

Adjusts test infrastructure/configuration to explicitly disable async inserts in many integration/stateless tests (new disable_async_inserts.xml, install script wiring, and per-test user configs) to keep tests deterministic under the new default.

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