Support multi-repo and multi-root workspace workflows

[johnnyhuy]

OpenPi is aiming at real multitasking across repos and worktrees, and the notes repeatedly point to multi-root style workflows.

Starter scope:

• define how multiple repos should appear in one workspace view
• decide how context recovery should behave across them
• avoid making monorepo and multi-repo setups feel like edge cases

Sources:

• Meetings/2026-04-20 - Leong Chiew build manifest rollout, Velo priorities, and AI native repo patterns.md
• Meetings/2026-04-20 - Lucy and Johnny - Claude Code workspace and chat history troubleshooting.md

Assignee: johnnyhuy