docs(browser): clarify local-only screenshots

Author: MagMueller

packages/opencode/src/tool/browser-execute.txt

@@ -4,4 +4,4 @@ Usage:
 - Use this tool whenever the task requires driving a real browser.
 - Use this tool to read webpages that block the webfetch tool.
 - IMPORTANT: you MUST use the skill tool first to load the `browser-execute` skill. This tool will fail if you did not read those directions first.
-- Returns console output from the snippet; screenshots attach automatically unless `Page.captureScreenshot({ attachToContext: false })` keeps them local.
+- Screenshots attach automatically; `Page.captureScreenshot({ attachToContext: false })` returns one only to the snippet and does not save it.