Workspace-scope legibility — empty workspaces and stale org restores should explain themselves, not look broken

Switching to humain-vc (0 orgs) made the workbench look dead: 'Filter 0 orgs', 'no orgs match', and a red 'organization not found: new-america' for the restored last-worked org. All three are per-workspace visibility working correctly — the plan is to make the correct behavior say so.