Implement "OR filter relationships" in DateQuery

[burhandodhy]

Description of the Change

This PR adds support for the relationship OR in Date Query.

Closes #4076

How to test the Change

Changelog Entry

Added - Implement "OR filter relationships" in DateQuery

Credits

Props @burhandodhy @eartahhj

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[Copilot]

Pull Request Overview

This PR implements support for "OR filter relationships" within the DateQuery functionality, enabling date queries to combine conditions using a logical OR. Key changes include:

• Adding test cases in TestPost.php to validate various OR-based date query scenarios.
• Extending the parse_date method in Post.php to account for an "or" key.
• Implementing the OR relation clause in DateQuery.php that builds appropriate Elasticsearch filters.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/php/indexables/TestPost.php	New test cases validating OR relation behavior in date queries.
includes/classes/Indexable/Post/Post.php	Updated parse_date to return value for an "or" filter, enabling OR logic.
includes/classes/Indexable/Post/DateQuery.php	New OR relation branch added to build Elasticsearch "should" clauses.

Comments suppressed due to low confidence (1)

includes/classes/Indexable/Post/DateQuery.php:137

• [nitpick] Consider adding a comment to explain the logic behind constructing the 'should' clauses for the OR relation. This documentation would clarify the intent and structure for future maintainers.

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[felipeelia]

Can we add @since tags to the tests please, @burhandodhy ?

[felipeelia]

@burhandodhy can you please fix this git conflict so we can merge this one? Thanks!