♲ Refactor configuration to use viper with context propagation

- Replace global ConfigPath and Overrides with viper-based configuration
- Add viper.New() to create configurable viper instances
- Store viper and unmarshaled Config struct in context for testability
- Add RetrieveFromContext and AddToContext helper functions
- Update files.Append to accept context and retrieve config from it
- Update formatters.Preferred and formatters.New to accept context
- Add PersistentPreRunE in CLI to create and configure viper instance
- Support -c flag for custom config file path
- Support -v flag for config value overrides
- Update all test files to create viper and add to context
- Remove unused config types and load functions
- Add viper as dependency with automatic env var support (MYLOG_*)

config/types.go

@@ -2,15 +2,15 @@ package config
 
 type Config struct {
 	Input      Input
-	Outputs    Outputs `toml:"output"`
+	Outputs    Outputs `mapstructure:"output"`
 	Formatters Formatters
 }
 
 type Input struct {
-	Path      string `env:"LOG_PATH"`
-	Recurse   bool   `env:"LOG_RECURSE"`
-	Ext       string `env:"LOG_EXT"`
-	DotFolder bool   `env:"LOG_DOT_FOLDER"`
+	Path      string
+	Recurse   bool
+	Ext       string
+	DotFolder bool `mapstructure:"dotFolder"`
 }
 
 type Outputs map[string]Output
@@ -20,16 +20,4 @@ type Output struct {
 	Config  map[string]any
 }
 
-type Stdout struct {
-	Format string `env:"LOG_STDOUT_FORMAT" mapstructure:"format"`
-}
-
-type stdoutEnabled struct {
-	Enabled bool `env:"LOG_STDOUT_ENABLED"`
-}
-
 type Formatters map[string]map[string]any
-
-type JsonFormat struct {
-	PrettyPrint bool `env:"LOG_JSON_PRETTY_PRINT" mapstructure:"pretty_print"`
-}