fix(schema): drop PARTITIONS N from PostgreSQL hash partitioning

The shared Schema\Trait\Partitioning emits `PARTITIONS N` after the
PARTITION BY clause when a count is set — but that's MySQL-only
syntax. PostgreSQL rejects it: hash partitions are declared with
separate `CREATE TABLE … PARTITION OF parent FOR VALUES WITH
(modulus N, remainder R)` statements.

Override compileCreatePartitioning in Schema\PostgreSQL to omit the
count clause so $table->partitionByHash($expr, 4) silently drops the
4 instead of generating invalid DDL.

Includes a regression test asserting the count is not emitted.

Author: abnegate

.claude/scheduled_tasks.lock

@@ -0,0 +1 @@
+{"sessionId":"1d4a85b1-8448-43af-af56-fde14c42dbc3","pid":21827,"procStart":"Fri May  8 10:26:06 2026","acquiredAt":1778287476666}

src/Query/Schema/PostgreSQL.php

@@ -588,4 +588,19 @@ public function dropPartition(string $table, string $name): Statement
             executor: $this->executor,
         );
     }
+
+    /**
+     * PostgreSQL accepts `PARTITION BY {RANGE|LIST|HASH} (expr)` but not the
+     * `PARTITIONS N` count modifier — that is MySQL-only. Override the shared
+     * trait to omit the count.
+     */
+    #[\Override]
+    public function compileCreatePartitioning(Table $table): string
+    {
+        if ($table->partitionType === null) {
+            return '';
+        }
+
+        return 'PARTITION BY ' . $table->partitionType->value . '(' . $table->partitionExpression . ')';
+    }
 }

tests/Query/Schema/PostgreSQLTest.php

@@ -1028,6 +1028,24 @@ public function testCreateTableWithPartitionByHash(): void
         $this->assertSame('CREATE TABLE "events" ("id" BIGINT GENERATED BY DEFAULT AS IDENTITY NOT NULL, PRIMARY KEY ("id")) PARTITION BY HASH(id)', $result->query);
     }
 
+    public function testCreateTableWithPartitionByHashIgnoresCount(): void
+    {
+        // PostgreSQL does not support `PARTITIONS N` (MySQL-only). The count
+        // argument must be silently dropped from the generated DDL.
+        $schema = new Schema();
+        $result = $schema->table('events')
+            ->id()
+            ->partitionByHash('id', 4)
+            ->create();
+        $this->assertBindingCount($result);
+
+        $this->assertSame(
+            'CREATE TABLE "events" ("id" BIGINT GENERATED BY DEFAULT AS IDENTITY NOT NULL, PRIMARY KEY ("id")) PARTITION BY HASH(id)',
+            $result->query,
+        );
+        $this->assertStringNotContainsString('PARTITIONS', $result->query);
+    }
+
     public function testAlterWithForeignKeyOnDeleteAndUpdate(): void
     {
         $schema = new Schema();