feat(search): add COLLECT reducer for FT.AGGREGATE (Redis 8.8+)

[ndyakov]

Add the new in-group sorting reducer for FT.AGGREGATE introduced in Redis 8.8. COLLECT unwinds grouped documents after GROUPBY and projects them as an array of key/value maps, with optional FIELDS, DISTINCT, SORTBY, and LIMIT clauses.

The existing FTAggregateReducer plumbing already passes Args verbatim after the reducer name, so the only changes needed are:

• Add SearchCollect to the SearchAggregator enum.
• Map SearchCollect.String() to "COLLECT".

Unit tests cover the String() mapping for every SearchAggregator constant and assert that FTAggregateWithArgs emits the expected REDUCE COLLECT ... AS ... clause for a representative query.

See: https://redis.io/docs/latest/develop/whats-new/8-8/

p.s. no integration tests as of now this should be enabled on the redis side to pass.

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Note

Low Risk
Enum and string mapping only; aggregate command assembly is unchanged and covered by new unit tests. COLLECT requires Redis 8.8+ on the server.

Overview
Adds client support for Redis 8.8’s COLLECT FT.AGGREGATE group reducer by extending SearchAggregator with SearchCollect and mapping it to "COLLECT" in String(). Callers can use the existing FTAggregateReducer / GroupBy options; reducer Args (e.g. FIELDS, SORTBY, LIMIT) are still passed through unchanged after REDUCE COLLECT.

Unit tests assert every aggregator’s String() output (including COLLECT) and that FTAggregateWithArgs builds the expected REDUCE COLLECT … AS … command for a representative grouped query.

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[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[Copilot]

Pull request overview

Adds client support for Redis 8.8+ FT.AGGREGATE COLLECT reducer by extending the existing SearchAggregator enum and its string mapping, plus unit tests validating reducer name rendering and command argument emission.

Changes:

• Add SearchCollect to the SearchAggregator enum.
• Map SearchCollect.String() to "COLLECT".
• Add unit tests for SearchAggregator.String() and FTAggregateWithArgs emitting REDUCE COLLECT ... AS ....

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
search_commands.go	Adds SearchCollect enum value and String() mapping to "COLLECT".
search_commands_unit_test.go	Adds unit tests for the new enum mapping and for FTAggregateWithArgs emitting a REDUCE COLLECT clause.

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