Audit test suite performance

[dominikletica]

Summary

Audited the PHPUnit suite for low-value coverage, accidental test discovery, and state-leak risks. Narrowed discovery to real *Test.php files, removed .codex helper-script coverage from the project test suite, trimmed UI/CSS/Stimulus-heavy assertions, consolidated duplicate route-smoke checks, and moved one setup validation case from a browser/controller test to a lighter factory-level test.

Also added safer cleanup for ZIP installer integration tests so failed assertions do not leave temporary package directories, upload roots, or package rows behind.

Testing

• bin/phpunit: Passed (791 tests, 4876 assertions, peak 121 MB)
• Other: Targeted PHPUnit runs for changed controller/setup/package tests passed
• Other: bin/lint on changed PHP files passed
• Other: git diff --check passed

Documentation

• Updated project readme (README.md)
• Updated feature drafts (dev/draft/*.md)
• Updated class map (dev/CLASSMAP.md)
• Updated worklog (dev/WORKLOG.md)
• Updated dev/user manuals (dev/manual/*.md / docs/*.md)
• Updated agent audit notes (.codex/test-suite-performance-audit-2026-06-01.md)

Additional Checks

• Security/privacy considerations
• Follow-up tasks captured in WORKLOG
• Linked issues / discussions
• Updated / aligned translations

Review Notes

No production behavior changes are intended. Remaining performance hotspots are mostly valuable integration coverage, especially setup/backend flows and the ZIP installer overwrite/dependency scenario. A future package-installer fixture strategy is deferred rather than weakening that coverage in this PR.