fix(core): report full relative paths in integrity checker for apps

[gitedmond]

Prepend the relative app folder and app ID to reported filenames when verifying app signatures to report full relative paths in the integrity checker.

Assisted-by: Antigravity:Gemini-3.5-Flash

• Resolves: [Bug]: List of missing files does not always show correct file path #62318

Summary

Prepend the relative app folder and app ID to reported filenames when verifying app signatures. This ensures the integrity check list output reports the full, correct path (e.g. apps/twofactor_totp/js/... instead of js/...) for missing or modified app-specific files.

Right now, if an app file fails verification, the integrity scanner only reports the path inside the app folder itself (like js/... instead of apps/twofactor_totp/js/...). This pr just prepends the app's relative directory to the path so you actually know where to look when files go missing.

Changes

• Updated the differences scanner loop in verify() inside lib/private/IntegrityCheck/Checker.php to prefix reported app filenames with their relative directory path resolved via the EnvironmentHelper (or standard apps/ layout).
• Configured environment helper mocks and updated expected paths inside tests/lib/IntegrityCheck/CheckerTest.php tests to align with the new prefixed path format.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits (Note: You must run git commit --amend -s on the branch to add your DCO signature)
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI