feat: support common subexpression elimination

[SkyFan2002]

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Summary

Complex queries often contain repeated or similar subexpressions. Evaluating each common subexpression once and reusing its result may speed up execution.

WIP...

fixes: #17661

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• Bug Fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• Documentation Update
• Refactoring
• Performance Improvement
• Other (please describe):

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This change is 

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Docker Image for PR

• tag: pr-18821-ee5fbde-1759654495

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🤖 Smart Auto-retry Analysis

Workflow: 18400658113

📊 Summary

• Total Jobs: 6
• Failed Jobs: 1
• Retryable: 0
• Code Issues: 1

❌ NO RETRY NEEDED

All failures appear to be code/test issues requiring manual fixes.

🔍 Job Details

• ❌ explain / cloud: Not retryable (Code/Test)

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Docker Image for PR

• tag: pr-18821-270046a-1760087471

note: this image tag is only available for internal use.