fix(workspace): stop false stage-mismatch warning, cap info panel height

Undeclared lanes default stage to the DB sentinel "idle", which never
matches a pipeline node — skip the mismatch warning in that case
instead of showing a false lane-action-failed banner. Also cap the
expandable lane-info block so it can't squeeze the console/split-view
out of the fixed-height detail panel.

client/src/pages/Workspace.tsx

@@ -439,7 +439,10 @@ export function Workspace() {
     try {
       const { lane } = await api.lanes.update(id, { pipeline });
       await refreshLanes();
-      if (!lane.pipeline_nodes.some((n) => n.state === "current")) {
+      // `stage` defaults to the DB sentinel "idle" until a driving session ever
+      // calls `ccam stage` — that's the normal state for most lanes and never
+      // matches a real pipeline node, so it isn't a mismatch worth surfacing.
+      if (lane.stage !== "idle" && !lane.pipeline_nodes.some((n) => n.state === "current")) {
         setLaneActionError(
           tLanes("pipelinePicker.stageMismatch", {
             stage: lane.stage,
@@ -559,7 +562,7 @@ export function Workspace() {
               </div>
             </div>
             {showInfo && (
-              <>
+              <div className="max-h-[45vh] shrink-0 overflow-y-auto">
                 <div className="mb-3 flex flex-wrap items-baseline gap-2">
                   <span className="text-[11px] font-semibold uppercase tracking-widest text-fg-muted">
                     {tLanes("cardId", { id: currentLane.id })}
@@ -688,7 +691,7 @@ export function Workspace() {
                       ))}
                     </div>
                   )}
-              </>
+              </div>
             )}
             <div className="flex min-h-0 flex-1 flex-col gap-2 border-t border-border pt-3">
               <ConsoleArea