[FEATURE] Allow launching the app preview from a new session or independently of session lifecycle

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The preview feature currently only works once a session is already created and active. This creates a chicken-and-egg problem: I often want to see how the app is currently running before starting a new task, so I have visual context of the current state before asking Claude to change anything.

Right now I have to either start a throwaway session just to get the preview up, or run the app manually outside Claude Code, which defeats the point of having the preview integrated.

Proposed Solution

Decouple the preview from the session lifecycle. Ideas:

• Make the preview a project-level toggle that persists across sessions and can be launched from the "New session" screen.
• Allow starting the preview from the landing view ("¿Qué sigue, Fede?" / "What's next?") before any session exists.
• Keep the preview running when a session ends, so the next session inherits the already-running dev server.

Alternative Solutions

Current workarounds:

1. Starting a throwaway/dummy session just to get the preview up before the real work begins, which pollutes the session history.
2. Running the dev server manually outside Claude Code in a separate terminal, which defeats the purpose of having the preview integrated.
3. Keeping an old session open just to preserve the running preview, even when I want to start fresh.

None of these are ideal — they all either waste time, clutter the workspace, or bypass the feature entirely.

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)
CLI commands and flags

Use Case Example

Example scenario:

1. I'm working on a full-stack monorepo (Zuno ERP) where the backend takes 20-30 seconds to start and the frontend another 10-15 seconds.
2. I open Claude Code to start a new task — for example, tweaking a UI component — but first I want to see the current state of the app to frame the change correctly.
3. Currently I have to create a session just to launch the preview, even though I haven't decided what to ask Claude yet.
4. With this feature, I could launch the preview from the landing screen ("What's next?") or have it persist from a previous session, and frame my task with full visual context before writing a single prompt.
5. This would save me time because startup cost is paid once per workday instead of once per session, and it would make UI/UX work significantly smoother since I could always see the current state before asking for changes.

Additional Context

_No response_