feat(mcp): let agents change thread workspaces#8680

fix(mcp): refresh status after checkout

test(vcs): match guarded branch creation

fix(vcs): reject option-like branch names

test(mcp): group worktree inventory coverage

fix(mcp): preserve changed handoff worktrees

fix(mcp): guard workspace transition ownership

docs(mcp): clarify credential liveness

fix(mcp): fail closed on checkout status errors

fix(mcp): preserve reviewed checkout composition

fix(mcp): recover threads from missing worktrees

fix(mcp): verify local checkout ownership

fix(mcp): fail closed on unresolved owners

fix(mcp): retain uncertain handoff branches

fix(mcp): preserve unowned checkout state

fix(mcp): guard nested checkout bindings

fix(mcp): guard checkout transitions atomically

docs(mcp): clarify checkout rollback cleanup

fix(mcp): serialize physical workspace checkout

feat(mcp): let agents change thread workspaces