chore: migrate egg-logger into monorepo

[killagu]

Migration Task

Migrate eggjs/egg-logger into the egg monorepo.

Source

• Repo: https://github.com/eggjs/egg-logger
• Package: egg-logger

Target

• Path: packages/logger/
• Package name: @eggjs/logger (or keep egg-logger)

Checklist

• Move source code to packages/logger/src/
• Update package.json (type: module, exports, publishConfig)
• Add minimal tsconfig.json extending root config
• Add vitest.config.ts and migrate tests
• Add src/types.ts for module augmentation
• Update root tsconfig.json references
• Update internal dependencies to use workspace:*
• Verify build and tests pass
• Archive the original repo after migration