e3.0.0 Added env variable support, improved cli arg, added tests, updated documentation.

doc.go

@@ -0,0 +1,60 @@
+// File: lixenwraith/config/doc.go
+
+// Package config provides thread-safe configuration management for Go applications
+// with support for multiple sources: TOML files, environment variables, command-line
+// arguments, and default values with configurable precedence.
+//
+// Features:
+//   - Multiple configuration sources with customizable precedence
+//   - Thread-safe operations using sync.RWMutex
+//   - Automatic type conversions for common Go types
+//   - Struct registration with tag support
+//   - Environment variable auto-discovery and mapping
+//   - Builder pattern for easy initialization
+//   - Source tracking to see where values originated
+//   - Configuration validation
+//   - Zero dependencies (only stdlib + toml parser + mapstructure)
+//
+// Quick Start:
+//
+//	type Config struct {
+//	    Server struct {
+//	        Host string `toml:"host"`
+//	        Port int    `toml:"port"`
+//	    } `toml:"server"`
+//	}
+//
+//	defaults := Config{}
+//	defaults.Server.Host = "localhost"
+//	defaults.Server.Port = 8080
+//
+//	cfg, err := config.Quick(defaults, "MYAPP_", "config.toml")
+//	if err != nil {
+//	    log.Fatal(err)
+//	}
+//
+//	host, _ := cfg.String("server.host")
+//	port, _ := cfg.Int64("server.port")
+//
+// Default Precedence (highest to lowest):
+//  1. Command-line arguments (--server.port=9090)
+//  2. Environment variables (MYAPP_SERVER_PORT=9090)
+//  3. Configuration file (config.toml)
+//  4. Default values
+//
+// Custom Precedence:
+//
+//	cfg, err := config.NewBuilder().
+//	    WithDefaults(defaults).
+//	    WithSources(
+//	        config.SourceEnv,     // Environment the highest priority
+//	        config.SourceCLI,
+//	        config.SourceFile,
+//	        config.SourceDefault,
+//	    ).
+//	    Build()
+//
+// Thread Safety:
+// All operations are thread-safe. The package uses read-write mutexes to allow
+// concurrent reads while protecting writes.
+package config