fix: oss boot error fixes

[Salazareo]

This pull request introduces several improvements and refactorings across the backend, focusing on dependency management, code modernization, and robustness in user and system services. The most significant changes are grouped below.

Dependency and Module Management Improvements:

• Updated AWS CloudWatch usage to the modern @aws-sdk/client-cloudwatch package, replacing the deprecated aws-sdk and updating initialization in both package.json and PerformanceMonitor.js. [1] [2] [3]
• Removed dynamic and redundant require statements in several modules, shifting to static imports for bcrypt, uuid, crypto, and socket.io, resulting in cleaner and more maintainable code. [1] [2]

User and Filesystem Service Enhancements:

• Improved the admin user creation logic in DefaultUserService.js to always ensure default files are present, even if the user already exists, and made the file creation process idempotent and robust against existing files/directories. [1] [2] [3]
• Refactored context field embedding in LLCWrite to use existing context values if present, supporting better operation chaining and overriding.

Code Robustness and Error Handling:

• Updated file and directory creation logic for default user files to gracefully handle "already exists" errors, ensuring that the setup process does not fail if files or directories are already present.
• Changed method names and access levels in SystemDataService for dereferencing, improving encapsulation and clarity. [1] [2]

Other Notable Improvements:

• Ensured the app icons directory is created with proper permissions using sudo, increasing reliability during system setup. [1] [2]
• Minor improvements and cleanups in stream utilities and router logic, removing unused imports and simplifying code paths. [1] [2] [3] [4] [5] [6]
• Made socket.io usage more robust by guarding against cases where the server might not be initialized.

These changes collectively improve maintainability, error handling, and system initialization robustness.