feat(stream): support XACKDEL and XDELEX commands

[kirito632]

What

This PR introduces the XACKDEL and XDELEX stream commands with configurable
PEL cleanup behaviors.

It also fixes an existing issue in XINFO CONSUMERS where consumer metadata
from different groups could leak into the same scan result.

XINFO CONSUMERS Fix

Root cause:
GetConsumerInfo() sets iterate_upper_bound by incrementing only the version
while keeping the sub-key prefix (which includes the group name) unchanged.
Since the version field precedes the sub-key in the InternalKey encoding
([version][sub_key]), consumer keys from other groups can fall within the
[version, version+1) range when their group name sorts lexicographically
at or after the target group's name prefix.

Fix:
Extract and validate the group name from each internal key during iteration,
filtering out consumers belonging to other groups.

XACKDEL / XDELEX

Supported deletion strategies:

• KEEPREF (default):
  Delete the stream entry only.

• DELREF:
  Delete the stream entry and remove it from all groups' PELs.

• ACKED:
  Delete the stream entry only if it has been acknowledged by all consumer groups.

Both commands return per-ID status codes:

• 1: entry deleted
• 2: entry retained (e.g. ACKED condition not satisfied)
• -1: entry not found or duplicate ID within the same request

Implementation Notes

• Pending-number decrements are aggregated in memory and flushed once
  through a single WriteBatch, avoiding repeated metadata updates during
  DELREF operations.

• Duplicate IDs within the same request are deduplicated to preserve
  idempotency and prevent stream metadata corruption.

• The originating command name (XACKDEL or XDELEX) is propagated into
  WriteBatchExtractor so replicas replay the exact same semantics.

• Internal stream metadata / PEL delete events are filtered out in
  WriteBatchExtractor by skipping synthetic subkeys whose entry-id prefix
  starts with UINT64_MAX, preventing invalid replicated XDEL commands.

Testing

Added Go integration tests covering:

• multi-group DELREF cleanup
• ACKED blocking semantics
• duplicate-ID idempotency
• invalid syntax handling
• XINFO CONSUMERS group isolation

AI-Assisted Contribution Disclosure

This contribution complies with the ASF AI-assisted contribution guidelines.

AI tools were used to assist with English phrasing and some test scaffolding.
The core C++ implementation, debugging, correctness analysis, and final verification
were independently completed by me.

[sonarqubecloud]

Quality Gate failed

Failed conditions
44.4% Coverage on New Code (required ≥ 50%)
22.8% Duplication on New Code (required ≤ 20%)

See analysis details on SonarQube Cloud

[kirito632]

I noticed the SonarCloud Quality Gate failed. I am currently working on a quick update to resolve this.

[aleksraiden]

@torwig please, review this pr, thanks

[jihuayu]

Hi @kirito632 Thanks for your contribution. However, I feel this PR is a bit too large. If possible, I’d suggest splitting it into two PRs, with each PR adding one command.

[kirito632]

Got it, thanks. I’ll split it into two PRs as suggested.

[kirito632]

Hi @jihuayu ,I have split this into #3502 (XDELEX) and #3504 (XACKDEL). Please review. Thanks!

[jihuayu]

@kirito632 Thanks. You can close this PR directly