Orchestrator worktree should be named orchestrator/{prefix}-orchestrator #184

Problem

The orchestrator session's worktree is not namespaced under an orchestrator/ directory with the expected naming convention.

Expected behavior

The orchestrator worktree path should follow the pattern:

orchestrator/{prefix}-orchestrator

For example, if the project prefix is ao-agents, the orchestrator worktree should be at:

orchestrator/ao-agents-orchestrator

Why it matters

• Disambiguation: Clearly separates the orchestrator session from worker/agent worktrees at a glance.
• Tooling conventions: Consistent naming allows orchestrator-vs-worker detection by path prefix, enabling smarter routing, cleanup policies, and display in UIs.
• Parity with worker convention: Workers already follow a structured naming scheme; the orchestrator should have an equally explicit, predictable path.