PHPLIB-1624 Add $rankFusion stage and $sigmoid expression

[GromNaN]

Fix PHPLIB-1624

•  Requires Add $rankFusion stage and $sigmoid expression mql-specifications#32

[GromNaN]

Usage of object is breaking the type system.

[alcaeus]

I presume this would be fixed by #1886?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 73.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.72%. Comparing base (12e5646) to head (d206247).
⚠️ Report is 1 commits behind head on v2.x.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/Builder/Stage/FluentFactoryTrait.php	0.00%	3 Missing ⚠️
src/Builder/Expression/SigmoidOperator.php	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               v2.x    #1885      +/-   ##
============================================
- Coverage     87.75%   87.72%   -0.04%     
- Complexity     3308     3315       +7     
============================================
  Files           447      449       +2     
  Lines          6607     6622      +15     
============================================
+ Hits           5798     5809      +11     
- Misses          809      813       +4     

Flag	Coverage Δ
6.0-replica_set	86.55% <73.33%> (-0.04%)	⬇️
6.0-server	82.58% <73.33%> (-0.03%)	⬇️
6.0-sharded_cluster	86.34% <73.33%> (-0.03%)	⬇️
8.0-replica_set	87.58% <73.33%> (-0.04%)	⬇️
8.0-server	83.32% <73.33%> (-0.03%)	⬇️
8.0-sharded_cluster	87.42% <73.33%> (?)

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[Copilot]

Pull request overview

Adds builder support for MongoDB 8.1’s new $rankFusion aggregation stage and $sigmoid aggregation expression, along with canonical JSON fixtures and tests to validate encoding through the BuilderEncoder.

Changes:

• Introduces RankFusionStage and wires it into the Stage factory + fluent pipeline builder.
• Introduces SigmoidOperator and wires it into the Expression factory.
• Adds pipeline fixture entries and new PHPUnit tests covering both features.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/Builder/Stage/RankFusionStageTest.php	New test asserting $rankFusion pipeline encoding matches canonical fixture.
tests/Builder/Stage/Pipelines.php	Adds canonical extended JSON fixture for $rankFusion example pipeline.
tests/Builder/Expression/SigmoidOperatorTest.php	New test asserting $sigmoid expression encoding matches canonical fixture.
tests/Builder/Expression/Pipelines.php	Adds canonical extended JSON fixture for $sigmoid example pipeline.
src/Builder/Stage/RankFusionStage.php	New auto-generated stage operator class for $rankFusion.
src/Builder/Stage/FluentFactoryTrait.php	Adds fluent rankFusion() stage helper.
src/Builder/Stage/FactoryTrait.php	Adds static rankFusion() stage factory method.
src/Builder/Expression/SigmoidOperator.php	New auto-generated expression operator class for $sigmoid.
src/Builder/Expression/FactoryTrait.php	Adds static sigmoid() expression factory method.