ci: exclude tests directory from PHPCS checks

Replace individual rule exclusions with a complete tests directory
exclusion, matching the approach used in other plugins like zoninator
and co-authors-plus. Test files have different coding requirements.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: GaryJones

.phpcs.xml.dist

@@ -35,19 +35,5 @@
 
 	<exclude-pattern>*/node_modules/*</exclude-pattern>
 	<exclude-pattern>*/vendor/*</exclude-pattern>
-
-	<!-- Allow PSR-4 naming in tests directory -->
-	<rule ref="WordPress.Files.FileName">
-		<exclude-pattern>tests/</exclude-pattern>
-	</rule>
-
-	<!-- Allow short ternary in test bootstrap -->
-	<rule ref="Universal.Operators.DisallowShortTernary">
-		<exclude-pattern>tests/bootstrap.php</exclude-pattern>
-	</rule>
-
-	<!-- Allow $_SERVER access in test bootstrap -->
-	<rule ref="WordPress.Security.ValidatedSanitizedInput">
-		<exclude-pattern>tests/bootstrap.php</exclude-pattern>
-	</rule>
+	<exclude-pattern>*/tests/*</exclude-pattern>
 </ruleset>