Tasks Module Stage 2: Subtasks

- Create task_subtasks table migration
- Create TaskSubtaskModel with CRUD operations
- Add subtask API methods: addSubtask, toggleSubtask, deleteSubtask
- Update TaskService to include subtasks in getTask()
- Add Routes for subtasks API
- Update show.twig with subtasks UI and JavaScript

app/Database/Migrations/2026-02-08-100005_CreateTaskSubtasksTable.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace App\Database\Migrations;
+
+use CodeIgniter\Database\Migration;
+
+class CreateTaskSubtasksTable extends Migration
+{
+    public function up()
+    {
+        $this->forge->addField([
+            'id' => [
+                'type' => 'INT',
+                'constraint' => 11,
+                'unsigned' => true,
+                'auto_increment' => true,
+            ],
+            'task_id' => [
+                'type' => 'INT',
+                'constraint' => 11,
+                'unsigned' => true,
+            ],
+            'title' => [
+                'type' => 'VARCHAR',
+                'constraint' => 255,
+            ],
+            'is_completed' => [
+                'type' => 'BOOLEAN',
+                'default' => false,
+            ],
+            'order_index' => [
+                'type' => 'INT',
+                'constraint' => 11,
+                'default' => 0,
+            ],
+            'created_at' => [
+                'type' => 'DATETIME',
+                'null' => true,
+            ],
+            'updated_at' => [
+                'type' => 'DATETIME',
+                'null' => true,
+            ],
+        ]);
+        $this->forge->addKey('id', true);
+        $this->forge->addForeignKey('task_id', 'tasks', 'id', 'CASCADE', 'CASCADE');
+        $this->forge->createTable('task_subtasks');
+    }
+
+    public function down()
+    {
+        $this->forge->dropTable('task_subtasks');
+    }
+}