test: upgrade acceptance on real machines #384

Why

The upgrade sequence must work for real users (design: The instructions).

In scope

On macOS, Linux and Windows: run the alpha.61 purge, then init on an existing project and a new one; record HOME changes.

Out of scope

Migration code.

Acceptance criteria

• Each machine ends with only the allowed user-level changes
• Findings have cards

Dependencies

Blocked by: #320, #378

Blocks: #390

Plan

• Release: 4.0.0-rc.1
• Size: size:M · Workstream: ws:ga-readiness
• Epic: docs: 4.0 GA readiness (epic) #303
• Card: GA-06 in the card inventory
• Sources: Design (docs(plans): project-scoped management design and its prerequisites #289) Upgrading from the user-level versions

Verification

• Dated receipt in docs/archive/