justfile: standardise test recipes to lint-php/lint-css/lint-js/test + add fix recipe

- Removed ambiguous aliases: phpstan, cs-check (both pointed to lint-php which
  also ran php-cs-fixer, making the names misleading)
- Removed syntax (php -l) — redundant, phpstan already catches parse errors
- Split lint-biome into lint-css and lint-js with correct paths
- Added lint meta-recipe that runs all three linters
- Added fix recipe: biome check --write (CSS/JS format+lint) + php-cs-fixer fix (PHP)
- Updated build-lint to delegate to lint-css + lint-js

TODO.md

@@ -18,3 +18,4 @@
 - [x] Add bulk select/delete to tmp cleanup dialog (like admin/index.php pattern)
 - [x] Move cleanup UI from modal to dedicated page (like add.php/edit.php)
 - [x] Replace <details> with <fieldset>/<legend> in cleanup fragments (like contenus.php)
+- [x] Standardise test group recipes: lint-php, lint-css, lint-js, test + add fix recipe