Fix environment variable mapping for read-only mode (#1067)

Fix environment variable mapping for read-only mode configuration

Add SetEnvKeyReplacer to viper configuration to properly map environment
variables with underscores to flag names with dashes. This enables the
documented GITHUB_READ_ONLY=1 environment variable to work correctly.

Without this fix, viper was looking for GITHUB_READ-ONLY (with dash) but
the documentation and standard convention use GITHUB_READ_ONLY (with
underscore).

Fixes issue where read-only mode was not being activated when using
GITHUB_READ_ONLY=1 in Docker containers.

Author: pinotelio

cmd/github-mcp-server/main.go

@@ -100,6 +100,7 @@ func init() {
 func initConfig() {
 	// Initialize Viper configuration
 	viper.SetEnvPrefix("github")
+	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
 	viper.AutomaticEnv()
 
 }