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_03_regulatory_constraints.md

@@ -0,0 +1,17 @@
+---
+title: '02 — Regulatory Constraints'
+description: 'Regulatory constraints that affect architecture decisions.'
+status: draft
+---
+
+# Regulatory Constraints
+
+> e.g., data privacy laws, industry standards.
+
+Regulatory constraints that impact the architecture of CalMiner include:
+
+1. **Data Privacy Compliance**: The architecture must ensure compliance with data privacy regulations such as GDPR or CCPA, which may dictate how user data is collected, stored, and processed.
+2. **Industry Standards**: Adherence to industry-specific standards and best practices may influence the design of data models, security measures, and reporting functionalities.
+3. **Auditability**: The system may need to incorporate logging and auditing features to meet regulatory requirements, affecting the architecture of data storage and access controls.
+4. **Data Retention Policies**: Regulatory requirements regarding data retention and deletion may impose constraints on how long certain types of data can be stored, influencing database design and data lifecycle management.
+5. **Security Standards**: Compliance with security standards (e.g., ISO/IEC 27001) may necessitate the implementation of specific security measures, such as encryption, access controls, and vulnerability management, which impact the overall architecture.