fix(stubs): detect actual database connection name

[guoyunhe]

🔗 Linked issue

❓ Type of change

• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

node ace add @adonisjs/queue will create a broken config:

// config/queue.ts
import env from '#start/env'
import { defineConfig, drivers } from '@adonisjs/queue'

export default defineConfig({
  default: env.get('QUEUE_DRIVER', 'database'),

  adapters: {
    database: drivers.database({
      connectionName: 'primary',
    }),
    sync: drivers.sync(),
  },

  worker: {
    concurrency: 5,
    idleDelay: '2s',
  },

  locations: ['./app/jobs/**/*.{ts,js}'],
})

database doesn't have a primary connection. app will fail to start.

The solution is to add detection logic, set connectionName to match actual connection from config/database.ts, and fallback to sqlite.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.