feat: Implement comprehensive architectural guidelines and clean code standards

- Establish feature-based architecture with clear separation between Logic, Data, and Shared layers
- Define directory structure conventions for controllers, entities, DTOs, managers, mappers, models, processors, providers, repositories, and services
- Implement Symfony 7.4+ compliance with proper Request handling (UI layer only)
- Enforce PHP 8+ attributes usage instead of annotations
- Set up proper DTO usage in UseCases with immutable properties
- Configure repository pattern with interfaces in Logic layer and implementations in Data layer
- Implement strict separation of concerns with UI layer handling Request objects exclusively
- Define clear naming conventions (PascalCase for feature names)
- Add shared components directory for reusable elements across features
- Establish HTTP status code constants usage instead of magic numbers
- Configure proper file placement for controllers in UI/Frontend, UI/Api, and UI/CLI subdirectories
- Enforce modern PHP practices with explicit return types and strict typing

This commit lays the foundation for a maintainable, scalable Symfony 7.4+ application following clean architecture principles and modern coding standards.

.continue/rules/symfony-74-request-handling.md

@@ -0,0 +1,8 @@
+k---
+globs: "**/UI/**/*Controller*.php"
+description: Ensures compliance with Symfony 7.4 deprecations and enforces
+  strict separation of concerns by isolating Request handling to the UI layer.
+alwaysApply: true
+---
+
+In Symfony 7.4+, never use the deprecated `Request::get()` method. Instead, use `$request->attributes` for route parameters, `$request->query` for query parameters, and `$request->getPayload()` for body data (JSON/Forms). Immediately convert request data into DTOs in Controllers. Never pass the Request object to Logic or Data layers.