Benchmark VB-parity startup, activation, and resource stability

## Objective

Measure baseline VB-framework and shared-model startup, splash overhead, next-instance activation latency, allocations, IPC resources, threads, handles, repeated launch/exit cycles, network-event subscriptions, and retained memory. Record reproducible before/after numbers and identify compatibility costs.

## Completion guidance

- Keep the implementation focused on the objective while allowing the assignee to improve the approach based on research.
- Document important decisions, rejected alternatives, dependencies, and follow-up work.
- Add or update tests and documentation appropriate to the work.
- Verify locally and in CI where the task changes code or generated artifacts.

No source files, tests, or entry points are named. Begin by locating the VB-parity and shared-model startup, activation, resource, and launch/exit-cycle paths, then define reproducible baseline measurements for the listed costs. Done means documented before/after numbers, compatibility findings, decisions and follow-up work, with appropriate tests or documentation and local/CI verification where applicable.

Written by the indexing model from the issue text.