Represent the published default page as a target-catalog placeholder with an explicit lifecycle. Materialize it only when an operation needs a live page owner; activate and close the placeholder directly, and create new targets without first constructing the default page.\n\nMake NavigationEngine initialization explicit so read-looking access cannot silently allocate the deferred runtime.
Expose a tab-level CDP frontend that rebinds to the selected page while direct page endpoints remain pinned to their target. Replay persistent Target configuration across rebinds and scope debugger waits to the exact attached target so existing replacement pages are not paused globally.
Carry foreground/background selection through renderer and protocol so auxiliary targets are activated independently of navigation. Match trusted input policy for platform modifiers, Shift, Alt, and window.open while preventing synthetic modified clicks from creating tab-unders.
ldm0