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__/Workspace.test.tsx

@@ -105,6 +105,15 @@ vi.mock("../../lib/api", async (importOriginal) => {
           recordCall("POST", `/api/lanes/stage`);
           return { ok: true };
         }),
+        pipelines: vi.fn().mockImplementation(async () => {
+          recordCall("GET", "/api/lanes/pipelines");
+          return { pipelines: [{ id: "default", name: "default", nodes: [] }] };
+        }),
+        update: vi.fn().mockImplementation(async (id: number, patch: Record<string, unknown>) => {
+          recordCall("PATCH", `/api/lanes/${id}`);
+          const lane = lanesToReturn.find((l) => l.id === id);
+          return { lane: { ...lane, ...patch } };
+        }),
         features: {
           list: vi.fn().mockImplementation(async (id: number) => {
             recordCall("GET", `/api/lanes/${id}/features`);