fix(client-v2,jdbc-v2): handle tagged errors in response streams

[jjj-n]

Summary

ClickHouse can append a tagged exception frame to an HTTP 200 response after streaming result data. This change detects and validates that frame so callers receive the server error when they reach it.

• Validate the frame against X-ClickHouse-Exception-Tag, its UTF-8 message byte length, and its end marker. Preserve ordinary payload bytes and mismatched markers.
• Keep normal reads demand-driven so a small response does not release its pooled connection prematurely.
• Report complete server errors even when the server terminates chunked HTTP framing without a final zero-length chunk. Abort the affected connection after a complete frame.
• Deliver already-decoded binary rows before reporting a prefetch error on the next advance. Preserve available LZ4 block data before reading another block.
• Map streamed server error 159 to JDBC SQLTimeoutException / HYT00, retaining vendor code and cause. Retain the existing error-60 mapping to 42S02.
• Document the behavior in CHANGELOG.md and docs/features.md.

Closes #2702
Closes #3077

Compatibility

No existing public method signatures, configuration defaults, or successful result formats are changed by this PR. HEADER_EXCEPTION_TAG and SQL_STATE_TIMEOUT are additive constants. Tagged server failures intentionally become exceptions instead of result data. The branch incorporates upstream main through ae682fcbd; its socket-buffer documentation and defaults are retained.

Validation

On the merge with current main (2026-09-18), Maven reactor verify completed successfully with JDK 17.0.19, Maven 3.9.16, UTC, and integration tests skipped:

Module	Tests	Failures / errors	Skipped
clickhouse-data	1,673	0	113
clickhouse-client	133	0	0
client-v2	701	0	0
jdbc-v2	1,896	0	0
Total	4,403	0	113

Command: mvn -t <local-jdk17-toolchains.xml> -pl jdbc-v2 -am -Duser.timezone=UTC -DskipITs=true -Dmaven.javadoc.skip=true verify.

The live-server integration tests could not be rerun on this merge because local Docker Desktop failed to start while initializing its Inference manager. No full integration-suite pass is claimed. GitHub CI still requires its own successful run.

The focused coverage includes split exception markers, mismatched tags, incomplete and invalid frames, UTF-8 lengths, compressed responses, interrupted HTTP chunk framing, last-row delivery, and JDBC error mapping.

On 2026-09-11, both originally reported integration failures (StatementTest#testConnectionExhaustion and StatementTest#testUpdateQueryWithResultSet) passed against ClickHouse 26.3.33.24 after the fixes. This historical result does not substitute for validation on the current merge.

[cursor]

Stale Bugbot comment from a previous run.

[chernser]

There are two tests failing:

[INFO] 
[ERROR] Failures: 
[ERROR]   StatementTest.testConnectionExhaustion:653 Exception expected
[ERROR]   StatementTest.testUpdateQueryWithResultSet:1333 Connection seems closed when should not expected [true] but found [false]
[INFO] 
[ERROR] Tests run: 469, Failures: 2, Errors: 0, Skipped: 0
[INFO] 

I've tested locally with the command:

~/tmp/clickhouse-java codex/issue-3077-stream-timeout$  mvn -DclickhouseVersion=26.3 clean verify

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 2 potential issues.

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