Enable filtered column persist via AbstractMapper::filterColumns()

Apply filterColumns() in extractColumns() so Filtered collections
generate partial INSERT/UPDATE statements with only the listed
columns plus the primary key.

Author: alganet

src/Mapper.php

@@ -261,7 +261,7 @@ private function extractColumns(object $entity, Collection $collection): array
             $c = $this->entityFactory->get($c, $primaryName);
         }
 
-        return $cols;
+        return $this->filterColumns($cols, $collection);
     }
 
     /** @param array<string, Collection> $collections */

tests/MapperTest.php

@@ -1205,6 +1205,36 @@ public function testFetchReturnsDbInstance(): void
         $this->assertInstanceOf(Db::class, $mapper->db);
     }
 
+    public function testFilteredPersistUpdatesOnlyFilteredColumns(): void
+    {
+        $mapper = $this->mapper;
+        $mapper->postTitles = Filtered::post('title');
+        $post = $mapper->postTitles()->fetch();
+        $this->assertEquals('Post Title', $post->title);
+
+        $post->title = 'Changed Title';
+        $mapper->postTitles()->persist($post);
+        $mapper->flush();
+
+        $row = $this->query('select * from post where id=5')->fetch(PDO::FETCH_ASSOC);
+        $this->assertEquals('Changed Title', $row['title']);
+        $this->assertEquals('Post Text', $row['text'], 'Non-filtered columns should remain unchanged');
+        $this->assertEquals(1, $row['author_id'], 'Non-filtered columns should remain unchanged');
+    }
+
+    public function testFilteredPersistInsertsOnlyFilteredColumns(): void
+    {
+        $mapper = $this->mapper;
+        $mapper->postTitles = Filtered::post('title');
+        $post = (object) ['id' => 99, 'title' => 'Partial Post', 'text' => 'Should not appear'];
+        $mapper->postTitles()->persist($post);
+        $mapper->flush();
+
+        $row = $this->query('select * from post where id=99')->fetch(PDO::FETCH_ASSOC);
+        $this->assertEquals('Partial Post', $row['title']);
+        $this->assertNull($row['text'], 'Non-filtered columns should not be inserted');
+    }
+
     private function query(string $sql): PDOStatement
     {
         $stmt = $this->conn->query($sql);