[建议 / Feature] Allow opening the built-in browser in a separate window (pop-out) instead of only the small side pane

提交前确认 · Pre-submission checklist

• 我已搜索过现有 issue，确认这不是重复提议 / I searched existing issues and confirmed this isn't a duplicate.
• 我已阅读 CONTRIBUTING.md / I've read CONTRIBUTING.md.

问题类别 · Category

UI / 界面体验 · UI / UX

涉及的 Agent 框架 · Agent framework

ZCode Agent（自研）

使用场景 · Use case

I use ZCode's built-in browser to read docs, check GitHub issues, and monitor dashboards while I work in the chat. The panel is very small in a normal window: it renders a 1280px-wide page inside a pane about 480px wide and is set to "Fit to window", so the page is scaled to roughly 38% and the text is barely readable. The only workarounds are switching the pane zoom to 100% (and then scrolling a lot) or widening the pane, which still leaves the browser squeezed next to the chat.

Concrete situations where this hurts:

• Reading documentation or API references side by side with the code the agent is writing.
• Watching a long build / dev-server log or a CI run while continuing to chat.
• Monitoring a dashboard (analytics, uptime, queue, Grafana) that needs real width.
• Following a multi-step sign-in / OAuth / SSO flow that expects a real browser window (I often end up copying the URL into Microsoft Edge).
• Filling in web forms where my password manager and browser extensions live in my normal browser.
• Comparing two pages (e.g. staging vs production) in two visible tabs at once.
• Checking a responsive layout at a real viewport size instead of a scaled-down thumbnail.
• Any task where I need to read/verify something visually in the browser while the agent keeps working in the chat.

建议方案 · Proposal

Give users a way to take the built-in browser out of the chat pane:

1. Add a "Pop out" / "Open in separate window" action (for example in the browser's "..." menu and/or a keyboard shortcut) that opens the current tab in a real, resizable OS window.
2. Additionally, add an "Expand" action that temporarily gives the browser the full ZCode window (chat hidden or collapsed), with an obvious way to return to the split view.
3. Make the separate window (or the expanded pane) use the same session/partition as the embedded browser, so the user stays logged in and multiple tabs/pages share cookies.
4. Support more than one pop-out window (one per tab) so several pages can be compared side by side.
5. Remember the user's chosen zoom and pane size, and default the panel zoom to 100% (instead of "Fit to window") whenever the pane is wide enough to make the page readable.

预期价值 · Expected value

Beyond the classic "log in to a site once" case, a full-size separate window makes ZCode usable for real browsing/verification work:

• Dev & ops: watch build/CI logs, server output and monitoring dashboards at real size while chatting with the agent.
• Documentation: read API/reference docs side by side with generated code.
• Research & QA: compare two pages (staging vs production, PR vs main) in two windows at the same time.
• Authentication: complete multi-step sign-in / OAuth / SSO and fill web forms using the user's normal passwords and extensions, without copying URLs into another browser.
• Visual verification: check responsive layouts at a real viewport and take accurate screenshots.

It removes the current ~38% scaled-down view and the need to leave ZCode entirely, keeping the whole workflow inside one app.

你认为的优先级 · Your perceived priority

中 · Medium

你使用的 ZCode 版本 / 环境 · ZCode version / environment

No response

补充材料 · Additional context

No response

No implementation files, tests, or entry points are named in the issue. Start by locating the built-in browser and its window/session management, then scope the proposal's pop-out, expansion, shared-session, multi-window, and zoom requirements; done means the selected behavior works without losing the embedded browser's session.