fix: writer/reader correctness and determinism issues

- merge: cloneTable keeps relationships; skip-tables applies to new schemas
- diff: detect schema description/owner changes
- prisma: reader no longer turns relation fields into columns, enum
  detection via declared names; writer type mapping is ordered
- typeorm writer: keep explicit SQL types that cannot be inferred
- drizzle: enum columns call the enum constant; reader resolves them
- mysql/mssql/sqlite writers: honour OutputPath, deterministic column
  and constraint order; mssql live execute covers full schema
- template: ToYAML recovers from panics; Merge nil-pointer loop
- regenerate drizzle fixtures

tests/assets/drizzle/schema-updated.ts

@@ -17,7 +17,7 @@ export const users = pgTable('users', {
   lastLoginAt: timestamp('last_login_at'),
   passwordHash: varchar('password_hash').notNull(),
   profile: jsonb('profile'),
-  role: pgEnum('UserRole')('role').notNull(),
+  role: userRole('role').notNull(),
   updatedAt: timestamp('updated_at').notNull().default(sql`now()`),
   username: varchar('username').notNull().unique(),
 });
@@ -131,7 +131,7 @@ export const orders = pgTable('orders', {
   notes: text('notes'),
   orderNumber: varchar('order_number').notNull().unique(),
   shippingAddress: jsonb('shipping_address').notNull(),
-  status: pgEnum('OrderStatus')('status').notNull().default('pending'),
+  status: orderStatus('status').notNull().default('pending'),
   totalAmount: numeric('total_amount').notNull(),
   updatedAt: timestamp('updated_at').notNull().default(sql`now()`),
   userId: integer('user_id').notNull().references(() => users.id),