Revert "Build a TYPO3 v13 extension: “Frontend QA – Visual Diff”. Backend module accepts two base URLs and a sitemap or manual list. A Scheduler task crawls pages, renders screenshots (before/after) per viewport using Imagick, computes pixel diff with toleranc..."

[priebera1]

Reverts #1

[priebera1]

Build a TYPO3 v13 extension “devsk_visualdiff” (issues-only, Scheduler-first). Goal: compare two bases (A,B) and show ONLY pages with broken frontend.

Constraints:

• NO Chromium/Node. Render HTML→PNG via wkhtmltoimage; compute diff via PHP Imagick/GD.
• Store outputs under var/visual-diff/job-/run-// (before.png, after.png, diff.png, meta.json).

Implement:

• DB: tx_visualdiff_job (bases, sitemap/manual URLs, filters, viewports, tolerance, concurrency, headers/cookies, stabilizers, storage_path, keep_history_runs, active), tx_visualdiff_run (status, stats), tx_visualdiff_issue (run/job, url, viewport, percent_changed, bbox_count, max_box_area, before/after/diff paths, bbox_json, resolved, error_message).
• Scheduler: RunVisualDiffJobTask (crawl+render+diff), Resume task, Purge history. CLI: bin/typo3 lia-visualdiff:run --job=.
• Rendering: wkhtmltoimage with --javascript-delay and optional --user-style-sheet (qa-freeze.css disables animations & hides dynamic UI). Headers/cookies injection supported.
• Diff: Imagick compare (AE metric) + fuzz tolerance; produce heatmap diff.png; binarize+morphology to get connected components → bbox_json. Heuristics “broken”: percent≥1.5% OR maxBoxArea≥2% OR bboxCount≥5 (configurable).
• Cache/skip by HTML hash A/B; sitemap chunking; concurrency control; retries/timeouts; SSRF guard/host whitelist.
• BE module: default view lists ONLY issues (unresolved first) with URL, viewport, badges (%, bbox), thumb of diff.png; filters (URL regex, viewport, percent range, status); detail view with before/after slider + diff overlay; AJAX toggle resolved; export CSV/JSON honoring filters.
• Files: ext_emconf.php, composer.json (require ext-imagick), ext_tables.sql, TCA for 3 tables, Services.yaml (RendererInterface=WkhtmltoimageRenderer), Scheduler registrations, Repositories, Controllers, Fluid templates, minimal ES6 for grid/slider (optional Pixelmatch in-browser preview only).

Deliver: full skeleton + key classes, configs, and QA freeze CSS.