Refine school search eligibility and status filtering

[mahmoodcli]

Description

This change refines school search eligibility so results are filtered using both phase of education and establishment status, rather than phase alone.

• Updates the school search to support both secondary and primary schools.
• Keeps secondary search behaviour unchanged.
• Shows primary schools as well when EnablePrimarySchools is enabled.
• Hides closed and excluded schools from search for both primary and secondary.
• Refactors search eligibility into a shared use case based on phase of education and establishment status.
• Updates indexing and tests to match the new search behaviour.

Related Trello Ticket

https://trello.com/c/PwkYe8wp

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• Tested on [Environment: Dev/Staging/Local]

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have verified accessibility requirements are met

Screenshots (if applicable)

[github-actions]

Deployments

Review app is available at these URLs:
https://get-school-improvement-insights-pr-248.test.teacherservices.cloud

[github-actions]

Code Coverage Report: Only Changed Files listed

Package	Coverage
Overall Coverage	🟢 77.59%

Minimum allowed coverage is 0%, this run produced 77.59%