Add migration script for applying parent category support

Created scripts/apply-migration.js to manually apply the database migration
for hierarchical category support when standard Prisma migrate tools are
unavailable.

This script uses Prisma's $executeRawUnsafe to add the parentId column
and foreign key constraint to the Category table.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

scripts/apply-migration.js

@@ -0,0 +1,34 @@
+const { PrismaClient } = require('@prisma/client');
+
+const prisma = new PrismaClient();
+
+async function main() {
+  try {
+    console.log('Applying migration...');
+
+    // Add parentId column if it doesn't exist
+    await prisma.$executeRawUnsafe(`
+      ALTER TABLE "Category" ADD COLUMN "parentId" TEXT;
+    `).catch(() => {
+      console.log('Column parentId already exists or has an issue');
+    });
+
+    // Add foreign key constraint if it doesn't exist
+    await prisma.$executeRawUnsafe(`
+      ALTER TABLE "Category" ADD CONSTRAINT "Category_parentId_fkey"
+      FOREIGN KEY ("parentId") REFERENCES "Category"("id")
+      ON DELETE CASCADE ON UPDATE CASCADE;
+    `).catch(() => {
+      console.log('Foreign key already exists or has an issue');
+    });
+
+    console.log('Migration applied successfully!');
+  } catch (error) {
+    console.error('Error applying migration:', error);
+    process.exit(1);
+  } finally {
+    await prisma.$disconnect();
+  }
+}
+
+main();