docs(driver): add package docs to driver interface and chrome backend

internal/driver/chrome/driver.go

@@ -1,3 +1,4 @@
+// Package chrome implements the device driver for web targets by driving Chrome over the DevTools protocol.
 package chrome
 
 import (

internal/driver/driver.go

@@ -1,3 +1,4 @@
+// Package driver defines the platform-agnostic device automation interface and shared types.
 package driver
 
 import (