feat(workspace): add 1/2/4-pane split terminal view toggle

client/src/i18n/locales/en/lanes.json

@@ -122,6 +122,7 @@
   "proof.ticketReport": "Task report",
   "splitView.emptyPane": "No lane selected for this pane.",
   "splitView.paneLaneLabel": "Pane lane selector",
+  "splitView.paneCount": "{{count}} pane",
   "splitView.pickLane": "Pick a lane",
   "statusDead": "DEAD",
   "title": "Lanes",

client/src/i18n/locales/vi/lanes.json

@@ -122,6 +122,7 @@
   "proof.ticketReport": "Báo cáo nhiệm vụ",
   "splitView.emptyPane": "Chưa chọn lane cho ô này.",
   "splitView.paneLaneLabel": "Bộ chọn lane cho ô",
+  "splitView.paneCount": "{{count}} ô",
   "splitView.pickLane": "Chọn lane",
   "statusDead": "ĐÃ CHẾT",
   "title": "Làn đường",

client/src/pages/Workspace.tsx

@@ -49,6 +49,8 @@ import PipelineMap from "../components/lanes/PipelineMap";
 import LaneCard from "../components/lanes/LaneCard";
 import LaneStripCard from "../components/lanes/LaneStripCard";
 import { AddLaneModal } from "../components/lanes/AddLaneModal";
+import { readSplitViewState, writeSplitViewState } from "../lib/splitViewStorage";
+import type { SplitViewState, SplitLayout } from "../lib/splitViewStorage";
 
 // ── Page ──────────────────────────────────────────────────────────────
 
@@ -80,6 +82,28 @@ export function Workspace() {
   const [defaultCwd, setDefaultCwd] = useState<string>("");
   const [paneHasActiveRun, setPaneHasActiveRun] = useState(false);
 
+  // Split view state
+  const [splitView, setSplitView] = useState<SplitViewState>(() => readSplitViewState());
+
+  const setLayout = useCallback((layout: SplitLayout) => {
+    setSplitView((prev) => {
+      const paneLaneIds = Array.from({ length: layout }, (_, i) => prev.paneLaneIds[i] ?? null);
+      const next = { layout, paneLaneIds };
+      writeSplitViewState(next);
+      return next;
+    });
+  }, []);
+
+  const setPaneLaneId = useCallback((index: number, id: number) => {
+    setSplitView((prev) => {
+      const paneLaneIds = [...prev.paneLaneIds];
+      paneLaneIds[index] = id;
+      const next = { ...prev, paneLaneIds };
+      writeSplitViewState(next);
+      return next;
+    });
+  }, []);
+
   // Pre-flight: probe binary + active runs + cwd suggestions + lanes on mount
   const refreshLanes = useCallback(async () => {
     try {
@@ -167,6 +191,20 @@ export function Workspace() {
     [refreshLanes]
   );
 
+  // Clean up stale pane lane IDs when lanes load
+  useEffect(() => {
+    if (!lanes.length) return;
+    setSplitView((prev) => {
+      const paneLaneIds = prev.paneLaneIds.map((id) =>
+        id !== null && lanes.some((l) => l.id === id) ? id : null
+      );
+      if (paneLaneIds.every((id, i) => id === prev.paneLaneIds[i])) return prev;
+      const next = { ...prev, paneLaneIds };
+      writeSplitViewState(next);
+      return next;
+    });
+  }, [lanes]);
+
   const refreshList = useCallback(() => {
     api.run
       .list()
@@ -514,6 +552,90 @@ export function Workspace() {
               </div>
             )}
           <div className="flex min-h-0 flex-col gap-2 border-t border-border pt-3">
+            <div className="flex items-center gap-1.5">
+              {([1, 2, 4] as const).map((n) => (
+                <button
+                  key={n}
+                  type="button"
+                  aria-pressed={splitView.layout === n}
+                  onClick={() => setLayout(n)}
+                  className={`rounded border px-2 py-1 text-xs ${
+                    splitView.layout === n
+                      ? "border-accent bg-accent/15 text-accent"
+                      : "border-border text-fg-secondary hover:border-border-light"
+                  }`}
+                >
+                  {tLanes("splitView.paneCount", { count: n })}
+                </button>
+              ))}
+            </div>
+            {splitView.layout === 1 ? (
+              <LaneConsolePane
+                lanes={lanes}
+                laneId={selectedLaneId}
+                showLaneSelector={false}
+                onLaneIdChange={(id) => setSelectedLaneId(id)}
+                onLaneCreated={(lane) =>
+                  setLanes((prev) => (prev.some((l) => l.id === lane.id) ? prev : [...prev, lane]))
+                }
+                binaryStatus={binaryStatus}
+                cwdSuggestions={cwdSuggestions}
+                activeRuns={activeRuns}
+                wsConnected={wsConnected}
+                defaultCwd={defaultCwd}
+                onHasActiveRunChange={setPaneHasActiveRun}
+              />
+            ) : (
+              <div
+                className={`grid flex-1 min-h-0 gap-3 ${
+                  splitView.layout === 2 ? "grid-cols-2" : "grid-cols-2 grid-rows-2"
+                }`}
+              >
+                {splitView.paneLaneIds.map((id, i) => (
+                  <LaneConsolePane
+                    key={i}
+                    lanes={lanes}
+                    laneId={id}
+                    showLaneSelector
+                    onLaneIdChange={(newId) => setPaneLaneId(i, newId)}
+                    onLaneCreated={(lane) =>
+                      setLanes((prev) =>
+                        prev.some((l) => l.id === lane.id) ? prev : [...prev, lane]
+                      )
+                    }
+                    binaryStatus={binaryStatus}
+                    cwdSuggestions={cwdSuggestions}
+                    activeRuns={activeRuns}
+                    wsConnected={wsConnected}
+                    defaultCwd={defaultCwd}
+                  />
+                ))}
+              </div>
+            )}
+          </div>
+        </section>
+      )}
+
+      {!currentLane && (
+        <div className="flex min-h-0 flex-col gap-2">
+          <div className="flex items-center gap-1.5">
+            {([1, 2, 4] as const).map((n) => (
+              <button
+                key={n}
+                type="button"
+                aria-pressed={splitView.layout === n}
+                onClick={() => setLayout(n)}
+                className={`rounded border px-2 py-1 text-xs ${
+                  splitView.layout === n
+                    ? "border-accent bg-accent/15 text-accent"
+                    : "border-border text-fg-secondary hover:border-border-light"
+                }`}
+              >
+                {tLanes("splitView.paneCount", { count: n })}
+              </button>
+            ))}
+          </div>
+          {splitView.layout === 1 ? (
             <LaneConsolePane
               lanes={lanes}
               laneId={selectedLaneId}
@@ -529,27 +651,33 @@ export function Workspace() {
               defaultCwd={defaultCwd}
               onHasActiveRunChange={setPaneHasActiveRun}
             />
-          </div>
-        </section>
-      )}
-
-      {!currentLane && (
-        <div className="flex min-h-0 flex-col gap-2">
-          <LaneConsolePane
-            lanes={lanes}
-            laneId={selectedLaneId}
-            showLaneSelector={false}
-            onLaneIdChange={(id) => setSelectedLaneId(id)}
-            onLaneCreated={(lane) =>
-              setLanes((prev) => (prev.some((l) => l.id === lane.id) ? prev : [...prev, lane]))
-            }
-            binaryStatus={binaryStatus}
-            cwdSuggestions={cwdSuggestions}
-            activeRuns={activeRuns}
-            wsConnected={wsConnected}
-            defaultCwd={defaultCwd}
-            onHasActiveRunChange={setPaneHasActiveRun}
-          />
+          ) : (
+            <div
+              className={`grid flex-1 min-h-0 gap-3 ${
+                splitView.layout === 2 ? "grid-cols-2" : "grid-cols-2 grid-rows-2"
+              }`}
+            >
+              {splitView.paneLaneIds.map((id, i) => (
+                <LaneConsolePane
+                  key={i}
+                  lanes={lanes}
+                  laneId={id}
+                  showLaneSelector
+                  onLaneIdChange={(newId) => setPaneLaneId(i, newId)}
+                  onLaneCreated={(lane) =>
+                    setLanes((prev) =>
+                      prev.some((l) => l.id === lane.id) ? prev : [...prev, lane]
+                    )
+                  }
+                  binaryStatus={binaryStatus}
+                  cwdSuggestions={cwdSuggestions}
+                  activeRuns={activeRuns}
+                  wsConnected={wsConnected}
+                  defaultCwd={defaultCwd}
+                />
+              ))}
+            </div>
+          )}
         </div>
       )}