Added Repo Scaffolding and Config File

[Howard-nolan]

Change Summary:

• Added initial project scaffold and /health endpoint.
• Introduced config loading (PORT) and basic logger.
• Implemented graceful shutdown with context and signal handling.

How It Works:

• main.go wires config, logger, and routes through a local ServeMux.
• Server listens on configurable port and shuts down cleanly on SIGINT/SIGTERM.

Additional Notes (optional):

• Foundation for future router, structured logs, and error handling in Phase 2.