Add flexible configuration with custom file path support

\n- Add DLC_CONFIG_FILE environment variable for custom config paths\n- Update config.go to support both default and custom config file locations\n- Update README.md and AGENTS.md with configuration documentation\n- Remove /Users/gabrielradureau/.dancelessonscoach/ directory approach\n- Add os import to config.go\n- Test all configuration scenarios

README.md

@@ -1,11 +1,16 @@
 # DanceLessonsCoach
 
-A simple Go project demonstrating idiomatic package structure and CLI implementation.
+A Go project demonstrating idiomatic package structure, CLI implementation, and JSON API with Chi router.
 
 ## Features
 
 - Greet function with default behavior
 - Command-line interface
+- JSON API with versioned endpoints
+- Chi router integration
+- Zerolog for high-performance logging
+- Viper for configuration management
+- Graceful shutdown with context
 - Unit tests
 - Go 1.26.1 compatible
 
@@ -20,8 +25,70 @@ cd DanceLessonsCoach
 go run ./cmd/greet
 ```
 
+## Optional Configuration
+
+The project supports configuration via YAML file, environment variables, or defaults.
+Configuration priority: file > environment variables > defaults
+
+### Configuration File
+
+By default, the application looks for `config.yaml` in the current working directory.
+
+Create a `config.yaml` file:
+
+```yaml
+server:
+  host: "0.0.0.0"
+  port: 8080
+shutdown:
+  timeout: 30s
+```
+
+Then start the server:
+
+```bash
+go run ./cmd/server
+```
+
+### Custom Config File Path
+
+To specify a custom config file path, use the `DLC_CONFIG_FILE` environment variable:
+
+```bash
+# Use a specific config file
+export DLC_CONFIG_FILE="/path/to/your/config.yaml"
+go run ./cmd/server
+
+# Or in one command
+DLC_CONFIG_FILE="/path/to/your/config.yaml" go run ./cmd/server
+```
+
+### Environment Variables
+
+You can also configure via environment variables with `DLC_` prefix:
+
+```bash
+# Set configuration via environment variables
+export DLC_SERVER_HOST="0.0.0.0"
+export DLC_SERVER_PORT=8080
+export DLC_SHUTDOWN_TIMEOUT=30s
+
+# Start the server
+go run ./cmd/server
+```
+
+### Configuration Priority
+
+1. **File-based configuration** (highest priority)
+2. **Environment variables** (override defaults)
+3. **Default values** (lowest priority)
+
+This means if you have both a config file and environment variables, the file takes precedence.
+
 ## Usage
 
+### CLI
+
 ```bash
 # Default greeting
 go run ./cmd/greet
@@ -32,6 +99,23 @@ go run ./cmd/greet John
 # Output: Hello John!
 ```
 
+### Web Server
+
+```bash
+# Start the server
+go run ./cmd/server
+
+# Test API endpoints
+curl http://localhost:8080/api/health
+# Output: {"status":"healthy"}
+
+curl http://localhost:8080/api/v1/greet
+# Output: {"message":"Hello world!"}
+
+curl http://localhost:8080/api/v1/greet/John
+# Output: {"message":"Hello John!"}
+```
+
 ## Testing
 
 ```bash
@@ -47,12 +131,20 @@ go test ./pkg/greet/
 ```
 DanceLessonsCoach/
 ├── cmd/
-│   └── greet/
-│       └── main.go          # CLI entry point
+│   ├── greet/              # CLI entry point
+│   │   └── main.go
+│   └── server/             # Web server entry point
+│       └── main.go
 ├── pkg/
-│   └── greet/
-│       ├── greet.go         # Core library
-│       └── greet_test.go    # Unit tests
+│   ├── config/             # Configuration management
+│   │   └── config.go
+│   ├── greet/              # Core greet functionality
+│   │   ├── api_v1.go       # API v1 handlers
+│   │   ├── greet.go        # Core service
+│   │   └── greet_test.go    # Unit tests
+│   └── server/             # Server implementation
+│       └── server.go
+├── config.example.yaml     # Configuration template
 ├── go.mod                   # Go module definition
 └── README.md                # Project documentation
 ```