Refactor architecture documentation and enhance security features

- Updated architecture constraints documentation to include detailed sections on technical, organizational, regulatory, environmental, and performance constraints.
- Created separate markdown files for each type of constraint for better organization and clarity.
- Revised the architecture scope section to provide a clearer overview of the system's key areas.
- Enhanced the solution strategy documentation with detailed explanations of the client-server architecture, technology choices, trade-offs, and future considerations.
- Added comprehensive descriptions of backend and frontend components, middleware, and utilities in the architecture documentation.
- Migrated UI, templates, and styling notes to a dedicated section for better structure.
- Updated requirements.txt to include missing dependencies.
- Refactored user authentication logic in the users.py and security.py files to improve code organization and maintainability, including the integration of OAuth2 password bearer token handling.

docs/architecture/02_constraints/02_04_environmental_constraints.md

@@ -0,0 +1,16 @@
+---
+title: '02 — Environmental Constraints'
+description: 'Environmental constraints that affect architecture decisions.'
+status: draft
+---
+
+# Environmental Constraints
+
+> e.g., deployment environments, cloud provider limitations.
+
+Environmental constraints affecting the architecture include:
+
+1. **Deployment Environments**: The architecture must accommodate various deployment environments (development, testing, production) with differing configurations and resource allocations.
+2. **Cloud Provider Limitations**: If deployed on a specific cloud provider, the architecture may need to align with the provider's services, limitations, and best practices, such as using managed databases or specific container orchestration tools.
+3. **Containerization**: The use of Docker for containerization imposes constraints on how the application is packaged, deployed, and scaled, influencing the architecture to ensure compatibility with container orchestration platforms.
+4. **Scalability Requirements**: The architecture must be designed to scale efficiently based on anticipated load and usage patterns, considering the limitations of the chosen infrastructure.