* Improve code style and PSR-12 compliance
- refactored code formatting to adhere to PSR-12 guidelines
- standardized coding conventions across the codebase
- added missing framework files and reverted markup changes
- reformatted arrays for enhanced readability
- updated language files for consistent styling and clarity
- minor miscellaneous improvements
- Replaced TRUE/FALSE constants with true/false keywords
- Replaced NULL constant with null keyword
- Replaced `<?php echo` in views with shortened `<?=`
- Added missing variable declaration
- Added missing function return type in declaration
- replaced `== true`, `== false`, `=== true` and `=== false` in if statements with simplified forms
- PHP 8.2 deprecates dynamically declared class properties. Adding these declarations removes deprecation warnings and makes the code PHP 8.3 compatible.
- Add Elvis operator to set search string to an empty string when it's value is null to get rid of an error in the search function call.
- Imported class for OSPOS config
- Replaced private with protected in parent controller's property.
- Removed unneeded TODO
- Refactored local variables
- Replaced ternary notation
- Removed unneeded comments
- Removed unneeded class property
- Removed unneeded @property declarations
- Fixed database version
- when the payments array was folded into sale_data there was an earlier payments[] reference in the foreach loop that didn't get folded in.
- Update PHPdoc
- Added ::class to remove polymorphic call warning
- Removed unreachable 'break;' statement after return statement.
- Added missing return type
- fixed missing assignment of mailchimp_api_key
