UOW-011: Implement Centralized Configuration Management System

[andhijeannot]

Overview

Phase: 4 - Architecture
Priority: Medium
Estimated Effort: 8-10 hours

Problem Description

The application lacks a centralized configuration management system with configuration scattered across multiple files and packages.

Acceptance Criteria

• Centralized configuration system with multiple sources
• Support for TOML, YAML, and JSON configuration files
• Environment variable integration with prefix support
• CLI flag override capabilities
• Configuration validation with clear error messages
• Profile-based configuration (dev, prod, test)

Files to Modify

• internal/config/config.go (new file)
• internal/config/sources.go (new file)
• internal/config/validator.go (new file)
• cmd/config.go (new CLI commands)

See roadmap/phase4-architecture/UOW-011-config-management.md for detailed implementation plan.