chore(setup): use In-Memory Config During Prepack

[aman19K]

Root Cause Analysis
The setup-repo scripts run:
npm i → pnpm package-lock-only → pnpm clean → pnpm install → pnpm prepack
During prepack, each package runs oclif manifest which accesses the config
Multiple processes trying to serialize/deserialize config simultaneously = corruption

This is a classic race condition issue in a monorepo environment where multiple packages are trying to access and modify the same configuration file simultaneously during the prepack phase.

Solution

In-Memory Config During Prepack:
No Temporary Files: During oclif manifest generation, the config will use pure in-memory storage (Map<string, any>).
No Cleanup Required: Since no files are created, there's no need for any cleanup.
Automatic Detection: Prepack mode is automatically detected via environment variables and process arguments.