fix: ensure migrate:make respects destroyOnExit config

[mx1700]

Summary

• When passing a pre-configured Kysely instance via kysely config option, migrate:make command would not destroy the instance after execution
• This causes the process to hang when connection pool settings like maxIdle create persistent connections
• Other commands like migrate:up, migrate:down, migrate:list already use usingKysely() wrapper which handles cleanup

Root Cause

The MakeCommand implementation directly called getConfigOrFail() and then proceeded to create the migration file without wrapping execution in usingKysely(). This skipped the destroyOnExit cleanup logic.

Fix

Wrap the migrate:make command execution in usingKysely() to ensure destroyOnExit logic is applied consistently with other commands.

// Before
const config = await getConfigOrFail(args)
// ... create migration file

// After  
await usingKysely(config, async () => {
  // ... create migration file
})

Testing

• All 67 existing tests pass
• Build completes successfully

Related

Addresses issue where migrate:make hangs after creating migration file when using connection pool settings like maxIdle=2 in database URL.