style: apply php-cs-fixer and PHPStan fixes (#289)

* style: apply php-cs-fixer to test files

Addresses drift flagged by the default PHP-CS-Fixer config — mostly
adds missing `: void` return types on pre-existing test methods.

No behavioural changes.

* fix: resolve phpstan errors surfaced by qa

- Drop the obsolete `Method ::test*() has no return type specified`
  ignore rule — every test method now declares a return type, so
  the pattern never matches and phpstan reports it as unmatched.
- Remove `?? []` from two reads of `CallToolRequest::$arguments`;
  the property is typed `array` (non-nullable), so the coalesce is
  a no-op that phpstan flags.

---------

Co-authored-by: DDEV User <nobody@example.com>

tests/Unit/Capability/Logger/ClientLoggerTest.php

@@ -22,7 +22,7 @@ use PHPUnit\Framework\TestCase;
  */
 final class ClientLoggerTest extends TestCase
 {
-    public function testLog()
+    public function testLog(): void
     {
         $session = $this->getMockBuilder(Session::class)
             ->disableOriginalConstructor()
@@ -39,7 +39,7 @@ final class ClientLoggerTest extends TestCase
         $logger->notice('test');
     }
 
-    public function testLogFilter()
+    public function testLogFilter(): void
     {
         $session = $this->getMockBuilder(Session::class)
             ->disableOriginalConstructor()
@@ -56,7 +56,7 @@ final class ClientLoggerTest extends TestCase
         $logger->debug('test');
     }
 
-    public function testLogFilterSameLevel()
+    public function testLogFilterSameLevel(): void
     {
         $session = $this->getMockBuilder(Session::class)
             ->disableOriginalConstructor()
@@ -73,7 +73,7 @@ final class ClientLoggerTest extends TestCase
         $logger->info('test');
     }
 
-    public function testLogWithInvalidLevel()
+    public function testLogWithInvalidLevel(): void
     {
         $session = $this->getMockBuilder(Session::class)
             ->disableOriginalConstructor()