feat(lanes): add pipeline-template picker to the Workspace lane header

Lets a lane's pipeline template be switched live from the dashboard
(the same PATCH /api/lanes/:id the CLI's `ccam lanes pipeline` uses),
so lanes created before the picker shipped don't need the terminal.
Both ship-feature skills now force their own template before their
first `ccam stage` call, so the human never has to pick correctly at
lane creation.

client/src/pages/__tests__/screens.snapshot.test.tsx

@@ -387,6 +387,7 @@ vi.mock("../../lib/api", async (importOriginal) => {
         create: r({ lane: {} }),
         update: r({ lane: {} }),
         stage: r({ lane: {} }),
+        pipelines: r({ pipelines: [] }),
         // A realistic shape: `{}` would crash blockingReason on `blocked` if any
         // screen ever opened the destructive modal.
         preflight: r({