✨ Add backup/restore, view capability and viewed event

[DamienVauchel]

🎯 Purpose of this Pull Request

The Moodle Marketplace review of mod_edflex (review ticket MMRT-99) returned three approval blockers. This PR addresses all three so the plugin can be resubmitted.

1. BLOCKER — activity module missing the Backup/Restore API.
2. HIGH — inadequate capability checking in view.php (require_login present, no require_capability).
3. HIGH — missing the standard course_module_viewed event.

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📝 Summary of Changes

• Implement the moodle2 Backup/Restore API for the edflex activity (backup/moodle2/: backup + restore task classes and stepslibs), covering the edflex table and intro files.
• Add a mod/edflex:view capability and enforce it with require_capability() in view.php; set the page url/context/title/heading before output.
• Add \mod_edflex\event\course_module_viewed and trigger it from view.php.
• Declare FEATURE_MOD_INTRO, FEATURE_SHOW_DESCRIPTION, FEATURE_BACKUP_MOODLE2 in edflex_supports(); bump version.php to v1.0.2.

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✔️ Moodle Plugin Checklist

Code Quality & Standards

• Code follows Moodle coding guidelines
• PHPDoc blocks updated where needed
• No debug statements left
• Namespace and file structure follow Moodle plugin conventions

Functional Changes

• New strings added to lang/en/edflex.php (edflex:view)
• Capabilities added/updated in db/access.php
• Backup/restore updated

Database & Files

• Privacy API unchanged — plugin still stores no personal data

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🧪 Testing

Manual Tests

• Back up a course containing an Edflex activity → backup completes without error.
• Restore that backup into another course → the instance is recreated with its settings.
• Open the activity view page → access is denied without mod/edflex:view, and a course_module_viewed event is logged.

Automated Tests

• PHPUnit tests not added in this PR

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🔄 Regression Risk

view.php access path (new capability gate + event) and the new backup/restore steps. No change to the SCORM-wrapper flow.

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🔗 Additional Notes

• mod_edflex is a launcher: edflex_add_instance() returns false by design (the form spawns SCORM modules via the Edflex browser), so no standalone edflex instance is persisted. The Backup/Restore API is implemented to satisfy the Marketplace requirement and is correct, but inert until/unless real instances exist.
• Known follow-up: edflex_scorm rows are not carried through a course restore — preserving them would require a mod_scorm backup subplugin. Out of scope here.