Fix system instruction loading failing on repeated calls

[gziolo]

What?

Fix load_system_instruction_from_file() silently returning an empty string when get_system_instruction() is called more than once with the same explicit filename in a single request.

Why?

The method used require_once to load instruction files. On the first call, PHP returns the file's return value (the instruction string). On subsequent calls, require_once returns true instead, causing is_string($content) to fail and the method to silently return ''.

How?

• Changed require_once to require, consistent with the automatic detection path which already uses require
• Added a regression test that calls get_system_instruction() twice with the same file and asserts both calls return the instruction
• Reduced duplication in Abstract_AbilityTest by extracting shared setup into setUp() and a temp file helper

Testing Instructions

1. Pull this branch down and run composer install
2. Run npm run test:php -- --filter='Abstract_AbilityTest' — all 10 tests should pass
3. Run the full test suite with npm run test:php — all tests should pass

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 57.70%. Comparing base (cde564d) to head (e283cd6).

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #358   +/-   ##
==========================================
  Coverage      57.70%   57.70%           
  Complexity       617      617           
==========================================
  Files             46       46           
  Lines           3173     3173           
==========================================
  Hits            1831     1831           
  Misses          1342     1342           

Flag	Coverage Δ
unit	57.70% <100.00%> (ø)

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[Copilot]

Pull request overview

Fixes repeated system-instruction loads returning an empty string by ensuring the instruction file’s return value is retrieved on every call, and adds/updates integration tests to prevent regressions.

Changes:

• Switch explicit system-instruction loading from require_once to require to preserve the file’s returned string across consecutive calls.
• Refactor Abstract_AbilityTest setup/cleanup to reduce duplication and add a regression test for consecutive calls.
• Add a temp file helper and centralized cleanup in tearDown().

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
includes/Abstracts/Abstract_Ability.php	Fixes repeated loads by using require so the returned instruction string is available on every call.
tests/Integration/Includes/Abstracts/Abstract_AbilityTest.php	Refactors common setup and adds coverage for the consecutive-call regression scenario.

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