feat: Implement system health metrics collection and reporting

- Added SystemHealthChecker to collect CPU, memory, disk, and load average metrics.
- Implemented methods to retrieve system information from /proc filesystem.
- Introduced a new method to collect metrics and return a SystemMetrics struct.
- Added tests for metric collection and parsing functions.

feat: Enhance agent runtime with state management and health monitoring

- Created AgentState struct to manage agent state with RwLock for concurrency.
- Refactored agent start logic to initialize cache and start health monitoring.
- Implemented connection loop with reconnection logic and health report handling.
- Added config update handling with nginx controller integration.

feat: Expand master client functionality for bidirectional streaming

- Updated MasterClient to support bidirectional streaming for health reports.
- Implemented registration logic with the master server.
- Added methods for sending messages and managing connection state.

feat: Improve nginx configuration management and rendering

- Enhanced ConfigManager for atomic symlink swaps and configuration validation.
- Implemented ConfigRenderer using Handlebars for dynamic nginx configuration generation.
- Added methods for applying, rolling back, and cleaning up configurations.
- Introduced tests for configuration rendering and validation.

feat: Implement nginx process control with lifecycle management

- Added methods to start, stop, reload, and test nginx configurations.
- Implemented graceful and immediate stop functionality.
- Enhanced error handling and logging for nginx operations.
- Added tests for deployment mode parsing and nginx lifecycle management.

config/development.toml

@@ -13,3 +13,11 @@ port = 8443
 [auth]
 jwt_secret = "development-secret-do-not-use-in-production"
 jwt_expiration_hours = 24
+
+[agent]
+name = "development-agent"
+data_dir = "./agent-runtime-data"
+
+[master]
+url = "http://localhost:8080"
+token = "token"