* chore: linting for `loadCustomConfig`
* refactor: decouple CDN init and variable/health checks from AppService
* refactor: move AppService to packages/data-schemas
* chore: update AppConfig import path to use data-schemas
* chore: update JsonSchemaType import path to use data-schemas
* refactor: update UserController to import webSearchKeys and redefine FunctionTool typedef
* chore: remove AppService.js
* refactor: update AppConfig interface to use Partial<TCustomConfig> and make paths and fileStrategies optional
* refactor: update checkConfig function to accept Partial<TCustomConfig>
* chore: fix types
* refactor: move handleRateLimits to startup checks as is an effect
* test: remove outdated rate limit tests from AppService.spec and add new handleRateLimits tests in checks.spec
