[chore] Add granular CI job toggles and verification scripts

[BrendanWalsh]

Quality of life improvements for the build process:

1. Pipeline parameterization (pipeline.yaml):

   • Add toggle parameters for each CI job type: testStyle, testUnit,
     testPython, testR, testE2E, testWebsiteSamples, websiteAutoDeploy,
     publishArtifacts
   • Jobs now check their corresponding parameter before running
   • Allows developers to skip expensive jobs during PR iteration

2. Pip install optimization (project/CodegenPlugin.scala):

   • Add --no-deps flag to pip install in installPipPackage task
   • Speeds up wheel installation by skipping dependency resolution

3. Verification scripts (tools/):

   • verify_python_mapping.py: Validates Java→Python class mapping
     for sentinel stages that have historically exposed export issues
   • verify_snapshot_alignment.py: Ensures wheel versions match JAR
     versions in local Maven cache (auto-detects Scala version)

[github-actions]

Hey @BrendanWalsh 👋!
Thank you so much for contributing to our repository 🙌.
Someone from SynapseML Team will be reviewing this pull request soon.

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• fix: Fix LightGBM crashes with empty partitions
• feat: Make HTTP on Spark back-offs configurable
• docs: Update Spark Serving usage
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• refactor: make python code generation rely on classes
• style: Remove nulls from CNTKModel
• test: Add test coverage for CNTKModel

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