feat: implement semantic rule validation for DQ rules (#1169)

[Vsatyam013]

Changes

Implements semantic validation for DQ rule expressions as part of issue #1169.
Adds a SemanticValidator class that checks SQL expressions for forbidden
destructive keywords (DROP, TRUNCATE, DELETE, UPDATE, INSERT, ALTER) before
rules are applied. Validation results are collected into ChecksValidationStatus
rather than raising exceptions, consistent with the existing validation contract.

Linked issues

Resolves #1169

Tests

• added unit tests

Documentation and Demos

• added/updated demos
• added/updated docs
• added/updated agent skills

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[ghanse]

Hi @Vsatyam013 , the linked issue focuses more on validating the entire ruleset to detect the following issues:

• Detect if a duplicate rule already exists with the same run config
• Detect if a similar rule exists with different arguments (e.g. a narrower threshold of is_in_range)

Can you make some changes to address these more specifically? I think it should be simpler because the check function inputs are mostly structured. We can document any limitations when users execute checks with Spark expressions.

[ghanse]

We update CHANGELOG automatically so these changes will need to be reverted.

[ghanse]

Not sure we want to do this level of validation in DQX. There are a lot of scenarios we would need to cover.

[mwojtyczka]

@Vsatyam013 do you plan to complete the PR, and address review comments? there was no update since 4 weeks.

[Vsatyam013]

Hi @mwojtyczka, sorry for the delay. I've reworked the implementation based on @ghanse's feedback. The SQL keyword validation approach has been removed and replaced with ruleset-level semantic checks, duplicate rule detection and conflicting rule detection (same function and column with different arguments). The validation is now integrated into validate_checks, save_checks, and load_checks with a configurable semantic_validation_mode parameter (warn, fail, or None). CHANGELOG changes have also been reverted.Can you review it?