# Task ID: 16
# Title: Create Configuration Management System
# Status: done
# Dependencies: 1
# Priority: high
# Description: Implement robust configuration handling with environment variables and .env files.
# Details:
Build configuration management including:
- Environment variable handling
- .env file support
- Configuration validation
- Sensible defaults with overrides
- Create .env.example template
- Add configuration documentation
- Implement secure handling of API keys

# Test Strategy:
Test configuration loading from various sources (environment variables, .env files). Verify that validation correctly identifies invalid configurations. Test that defaults are applied when values are missing.

# Subtasks:
## 1. Implement Environment Variable Loading [done]
### Dependencies: None
### Description: Create a module that loads environment variables from process.env and makes them accessible throughout the application. Implement a hierarchical structure for configuration values with proper typing. Include support for required vs. optional variables and implement a validation mechanism to ensure critical environment variables are present.
### Details:


## 2. Implement .env File Support [done]
### Dependencies: 16.1
### Description: Add support for loading configuration from .env files using dotenv or a similar library. Implement file detection, parsing, and merging with existing environment variables. Handle multiple environments (.env.development, .env.production, etc.) and implement proper error handling for file reading issues.
### Details:


## 3. Implement Configuration Validation [done]
### Dependencies: 16.1, 16.2
### Description: Create a validation system for configuration values using a schema validation library like Joi, Zod, or Ajv. Define schemas for all configuration categories (API keys, file paths, feature flags, etc.). Implement validation that runs at startup and provides clear error messages for invalid configurations.
### Details:


## 4. Create Configuration Defaults and Override System [done]
### Dependencies: 16.1, 16.2, 16.3
### Description: Implement a system of sensible defaults for all configuration values with the ability to override them via environment variables or .env files. Create a unified configuration object that combines defaults, .env values, and environment variables with proper precedence. Implement a caching mechanism to avoid repeated environment lookups.
### Details:


## 5. Create .env.example Template [done]
### Dependencies: 16.1, 16.2, 16.3, 16.4
### Description: Generate a comprehensive .env.example file that documents all supported environment variables, their purpose, format, and default values. Include comments explaining the purpose of each variable and provide examples. Ensure sensitive values are not included but have clear placeholders.
### Details:


## 6. Implement Secure API Key Handling [done]
### Dependencies: 16.1, 16.2, 16.3, 16.4
### Description: Create a secure mechanism for handling sensitive configuration values like API keys. Implement masking of sensitive values in logs and error messages. Add validation for API key formats and implement a mechanism to detect and warn about insecure storage of API keys (e.g., committed to git). Add support for key rotation and refresh.
### Details:


