During bootstrap layer migration, `defineStatusConstants()` was moved to `XC_Bootstrap` but its invocation was not added to `boot()`. This left `STATUS_SUCCESS`, `STATUS_FAILURE` and other status constants undefined, causing a fatal error on admin login.
Added `self::defineStatusConstants()` to the `CONTEXT_ADMIN` branch before `initAdminGlobals()`.
- Updated multiple files to use global variables for `$db` and `$rSettings` instead of calling `SettingsManager::getAll()` repeatedly.
- Removed unnecessary variable assignments and improved code readability.
- Deleted unused scripts for cleaning and scanning PHP file headers.
- Removed a file containing PHP syntax errors.
- Adjusted various repository and service classes to streamline database interactions.
Divarion-D