Add detailed godoc documentation to CLIEntry function

Expand the documentation comment for CLIEntry to provide more context
about what the function does, including its use of the fx dependency
injection framework, signal handling, and blocking behavior.

internal/routewatch/cli.go

@@ -53,7 +53,11 @@ func logDebugStats(logger *logger.Logger) {
 	}
 }
 
-// CLIEntry is the main entry point for the CLI
+// CLIEntry is the main entry point for the routewatch command-line interface.
+// It initializes the application using the fx dependency injection framework,
+// sets up signal handling for graceful shutdown, and starts the RouteWatch service.
+// This function blocks until the application receives a shutdown signal or encounters
+// a fatal error.
 func CLIEntry() {
 	app := fx.New(
 		getModule(),