Unify IDE preview and inspector on one extension-managed dft serve

Problem

Design and implement a single extension-managed dft serve runtime for both preview and inspector so the IDE stops mixing direct dft render calls with a separate inspect server lifecycle. Cover variable state, unsaved editor refresh semantics, route design, server discovery/reuse, and migration of preview/open-in-browser/inspector flows onto the shared server.

Context

Possible Solutions

Plan

Implementation Progress

QA Exploration

• QA exploration completed (or N/A for non-UI tasks)

Review Feedback

• Review cleared