fix: ConnectionRegistry robust to numeric-string ids

PHP coerces numeric-string array keys ("1") to int keys, so ids()/each()/clear()
could hand ints to remove(string) and TypeError. Cast to string in those paths.
Surfaced by the laravel-ws integration (connection ids are sequential numbers).
Regression test added. Suite: 20 tests.

rel learn-atc #1055 #1057

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Support/ConnectionRegistry.php

@@ -67,7 +67,8 @@ final class ConnectionRegistry implements \Countable
     /** @return array<int,string> */
     public function ids(): array
     {
-        return array_keys($this->items);
+        // Cast: PHP coerces numeric-string keys (e.g. "1") to int keys internally.
+        return array_map(strval(...), array_keys($this->items));
     }
 
     public function count(): int
@@ -82,7 +83,7 @@ final class ConnectionRegistry implements \Countable
     public function each(callable $callback): void
     {
         foreach ($this->items as $id => $connection) {
-            $callback($connection, $id);
+            $callback($connection, (string) $id);
         }
     }
 
@@ -102,7 +103,7 @@ final class ConnectionRegistry implements \Countable
     public function clear(): void
     {
         foreach (array_keys($this->items) as $id) {
-            $this->remove($id);
+            $this->remove((string) $id); // keys may be int (PHP numeric-string coercion)
         }
     }
 }

tests/ConnectionRegistryTest.php

@@ -55,6 +55,26 @@ final class ConnectionRegistryTest extends TestCase
         $this->assertSame(['x'], $added);
     }
 
+    public function test_numeric_string_ids_survive_ids_each_and_clear(): void
+    {
+        // PHP coerces numeric-string array keys ("1") to int keys internally, which
+        // used to hand ints to remove(string) during clear(). Regression guard.
+        $registry = new ConnectionRegistry;
+        $registry->add('1', new \stdClass);
+        $registry->add('2', new \stdClass);
+
+        $this->assertSame(['1', '2'], $registry->ids());
+
+        $seen = [];
+        $registry->each(function (object $conn, string $id) use (&$seen) {
+            $seen[] = $id; // must receive strings, not ints
+        });
+        $this->assertSame(['1', '2'], $seen);
+
+        $registry->clear(); // must not TypeError
+        $this->assertCount(0, $registry);
+    }
+
     public function test_each_visits_every_connection(): void
     {
         $registry = new ConnectionRegistry;