fix(worktree): fork workspace worktree boot

[kitlangton]

Summary

• Make workspace-adapter worktree creation return after git setup instead of waiting for boot/start scripts.
• Reuse createFromInfo from direct worktree creation so both entrypoints share the same async boot contract.
• Add regression coverage for direct and workspace worktree create, including a project start command that would previously block the response.

Testing

• bun run test test/project/worktree.test.ts test/server/worktree-endpoint-repro.test.ts
• bun run typecheck