feat(canvas): batch operations — multi-select + restart/pause/delete (Phase 20.3)

- Shift+click to toggle node selection (multi-select mode)
- BatchActionBar floating at bottom when >1 node selected
- Batch Restart All, Pause All, Delete All with ConfirmDialog
- Selected nodes get blue ring highlight
- Escape clears selection
- Pane click clears selection
- Dark theme, accessible (ARIA labels, focus rings)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

canvas/src/components/BatchActionBar.tsx

@@ -0,0 +1,124 @@
+"use client";
+
+import { useState } from "react";
+import { createPortal } from "react-dom";
+import { useCanvasStore } from "@/store/canvas";
+import { ConfirmDialog } from "./ConfirmDialog";
+import { showToast } from "./Toaster";
+
+type BatchAction = "restart" | "pause" | "delete" | null;
+
+export function BatchActionBar() {
+  const selectedNodeIds = useCanvasStore((s) => s.selectedNodeIds);
+  const clearSelection = useCanvasStore((s) => s.clearSelection);
+  const batchRestart = useCanvasStore((s) => s.batchRestart);
+  const batchPause = useCanvasStore((s) => s.batchPause);
+  const batchDelete = useCanvasStore((s) => s.batchDelete);
+
+  const [pending, setPending] = useState<BatchAction>(null);
+  const [busy, setBusy] = useState(false);
+
+  const count = selectedNodeIds.size;
+  if (count < 2) return null;
+
+  const confirmMessages: Record<NonNullable<BatchAction>, string> = {
+    restart: `Restart ${count} workspace${count !== 1 ? "s" : ""}? Each will briefly go offline while it restarts.`,
+    pause:   `Pause ${count} workspace${count !== 1 ? "s" : ""}? Their containers will be stopped.`,
+    delete:  `Permanently delete ${count} workspace${count !== 1 ? "s" : ""}? This cannot be undone.`,
+  };
+
+  const confirmLabels: Record<NonNullable<BatchAction>, string> = {
+    restart: "Restart All",
+    pause:   "Pause All",
+    delete:  "Delete All",
+  };
+
+  async function execute() {
+    if (!pending) return;
+    setBusy(true);
+    try {
+      if (pending === "restart") await batchRestart();
+      if (pending === "pause")   await batchPause();
+      if (pending === "delete")  await batchDelete();
+      showToast(`${pending.charAt(0).toUpperCase() + pending.slice(1)} applied to ${count} workspace${count !== 1 ? "s" : ""}`, "success");
+      clearSelection();
+    } catch {
+      showToast(`Batch ${pending} failed`, "error");
+    } finally {
+      setBusy(false);
+      setPending(null);
+    }
+  }
+
+  const bar = (
+    <div
+      role="toolbar"
+      aria-label="Batch workspace actions"
+      className="fixed bottom-6 left-1/2 -translate-x-1/2 z-[200] flex items-center gap-3 px-4 py-2.5 rounded-2xl bg-zinc-900/95 border border-zinc-700/70 shadow-2xl shadow-black/50 backdrop-blur-md"
+    >
+      {/* Selection count badge */}
+      <span className="text-[12px] font-semibold text-zinc-100 bg-blue-600/80 px-2.5 py-0.5 rounded-full tabular-nums">
+        {count} selected
+      </span>
+
+      <div className="w-px h-5 bg-zinc-700/60" aria-hidden="true" />
+
+      {/* Action buttons */}
+      <button
+        disabled={busy}
+        onClick={() => setPending("restart")}
+        className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-[12px] font-medium text-sky-300 bg-sky-900/30 hover:bg-sky-800/50 border border-sky-700/30 hover:border-sky-600/50 transition-colors disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-500/70"
+      >
+        <span aria-hidden="true">↻</span>
+        Restart All
+      </button>
+
+      <button
+        disabled={busy}
+        onClick={() => setPending("pause")}
+        className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-[12px] font-medium text-amber-300 bg-amber-900/30 hover:bg-amber-800/50 border border-amber-700/30 hover:border-amber-600/50 transition-colors disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-amber-500/70"
+      >
+        <span aria-hidden="true">⏸</span>
+        Pause All
+      </button>
+
+      <button
+        disabled={busy}
+        onClick={() => setPending("delete")}
+        className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-[12px] font-medium text-red-300 bg-red-900/30 hover:bg-red-800/50 border border-red-700/30 hover:border-red-600/50 transition-colors disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-red-500/70"
+      >
+        <span aria-hidden="true">✕</span>
+        Delete All
+      </button>
+
+      <div className="w-px h-5 bg-zinc-700/60" aria-hidden="true" />
+
+      {/* Deselect */}
+      <button
+        disabled={busy}
+        onClick={clearSelection}
+        aria-label="Clear selection"
+        title="Clear selection (Escape)"
+        className="p-1.5 rounded-lg text-[12px] text-zinc-400 hover:text-zinc-200 hover:bg-zinc-700/50 transition-colors disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-zinc-500/70"
+      >
+        ✕
+      </button>
+    </div>
+  );
+
+  return (
+    <>
+      {typeof window !== "undefined" ? createPortal(bar, document.body) : null}
+
+      <ConfirmDialog
+        open={!!pending}
+        title={pending ? confirmLabels[pending] : ""}
+        message={pending ? confirmMessages[pending] : ""}
+        confirmLabel={pending ? confirmLabels[pending] : "Confirm"}
+        confirmVariant={pending === "delete" ? "danger" : pending === "pause" ? "warning" : "primary"}
+        onConfirm={execute}
+        onCancel={() => setPending(null)}
+      />
+    </>
+  );
+}

canvas/src/components/Canvas.tsx

@@ -32,6 +32,8 @@ import { Toolbar } from "./Toolbar";
 import { ConfirmDialog } from "./ConfirmDialog";
 // Phase 20 components
 import { SettingsPanel, DeleteConfirmDialog } from "./settings";
+// Phase 20.3 batch operations
+import { BatchActionBar } from "./BatchActionBar";
 import { ProvisioningTimeout } from "./ProvisioningTimeout";
 
 const nodeTypes = {
@@ -133,7 +135,9 @@ function CanvasInner() {
 
   const onPaneClick = useCallback(() => {
     selectNode(null);
-    useCanvasStore.getState().closeContextMenu();
+    const state = useCanvasStore.getState();
+    state.closeContextMenu();
+    state.clearSelection();
   }, [selectNode]);
 
   // Team zoom-in: double-click a team node to zoom to its children
@@ -192,6 +196,8 @@ function CanvasInner() {
         const state = useCanvasStore.getState();
         if (state.contextMenu) {
           state.closeContextMenu();
+        } else if (state.selectedNodeIds.size > 0) {
+          state.clearSelection();
         } else if (state.selectedNodeId) {
           state.selectNode(null);
         }
@@ -336,6 +342,7 @@ function CanvasInner() {
       <Toaster />
       <ProvisioningTimeout />
       {!selectedNodeId && <CreateWorkspaceButton />}
+      <BatchActionBar />
 
       {/* Confirmation dialog for structure changes */}
       <ConfirmDialog

canvas/src/components/WorkspaceNode.tsx

@@ -47,6 +47,9 @@ export function WorkspaceNode({ id, data }: NodeProps<Node<WorkspaceNodeData>>)
   const nestNode = useCanvasStore((s) => s.nestNode);
   const isDragTarget = useCanvasStore((s) => s.dragOverNodeId === id);
   const isSelected = selectedNodeId === id;
+  // Batch selection (Phase 20.3)
+  const isBatchSelected = useCanvasStore((s) => s.selectedNodeIds.has(id));
+  const toggleNodeSelection = useCanvasStore((s) => s.toggleNodeSelection);
   const isOnline = data.status === "online";
 
   // Get children + hierarchy info (single stable selector avoids redundant re-renders)
@@ -68,7 +71,11 @@ export function WorkspaceNode({ id, data }: NodeProps<Node<WorkspaceNodeData>>)
       aria-pressed={isSelected}
       onClick={(e) => {
         e.stopPropagation();
-        selectNode(isSelected ? null : id);
+        if (e.shiftKey) {
+          toggleNodeSelection(id);
+        } else {
+          selectNode(isSelected ? null : id);
+        }
       }}
       onDoubleClick={(e) => {
         e.stopPropagation();
@@ -84,7 +91,11 @@ export function WorkspaceNode({ id, data }: NodeProps<Node<WorkspaceNodeData>>)
       onKeyDown={(e) => {
         if (e.key === "Enter" || e.key === " ") {
           e.preventDefault();
-          selectNode(isSelected ? null : id);
+          if (e.shiftKey) {
+            toggleNodeSelection(id);
+          } else {
+            selectNode(isSelected ? null : id);
+          }
         } else if (e.key === "ContextMenu") {
           e.preventDefault();
           const rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
@@ -103,6 +114,8 @@ export function WorkspaceNode({ id, data }: NodeProps<Node<WorkspaceNodeData>>)
         transition-all duration-200 ease-out
         ${isDragTarget
           ? "bg-emerald-950/40 border-2 border-emerald-400/60 ring-2 ring-emerald-400/20 scale-[1.03]"
+          : isBatchSelected
+          ? "bg-zinc-900/95 border-2 border-blue-500/80 ring-2 ring-blue-500/30 shadow-lg shadow-blue-500/15"
           : isSelected
           ? "bg-zinc-900/95 border border-blue-500/70 ring-1 ring-blue-500/30 shadow-lg shadow-blue-500/10"
           : "bg-zinc-900/90 border border-zinc-700/80 hover:border-zinc-500/60 shadow-lg shadow-black/30 hover:shadow-xl hover:shadow-black/40"

canvas/src/store/canvas.ts

@@ -71,6 +71,13 @@ interface CanvasState {
   viewport: { x: number; y: number; zoom: number };
   setViewport: (v: { x: number; y: number; zoom: number }) => void;
   saveViewport: (x: number, y: number, zoom: number) => void;
+  // ── Batch selection (Phase 20.3) ─────────────────────────────────────────
+  selectedNodeIds: Set<string>;
+  toggleNodeSelection: (id: string) => void;
+  clearSelection: () => void;
+  batchRestart: () => Promise<void>;
+  batchPause: () => Promise<void>;
+  batchDelete: () => Promise<void>;
   /** Agent-pushed messages keyed by workspace ID. ChatTab consumes and clears these. */
   agentMessages: Record<string, Array<{ id: string; content: string; timestamp: string }>>;
   consumeAgentMessages: (workspaceId: string) => Array<{ id: string; content: string; timestamp: string }>;
@@ -96,6 +103,38 @@ export const useCanvasStore = create<CanvasState>((set, get) => ({
   panelTab: "chat",
   dragOverNodeId: null,
   contextMenu: null,
+  // Batch selection
+  selectedNodeIds: new Set<string>(),
+  toggleNodeSelection: (id) => {
+    const prev = get().selectedNodeIds;
+    const next = new Set(prev);
+    if (next.has(id)) {
+      next.delete(id);
+    } else {
+      next.add(id);
+    }
+    set({ selectedNodeIds: next });
+  },
+  clearSelection: () => set({ selectedNodeIds: new Set<string>() }),
+  batchRestart: async () => {
+    const ids = Array.from(get().selectedNodeIds);
+    await Promise.allSettled(ids.map((id) => api.post(`/workspaces/${id}/restart`)));
+    for (const id of ids) {
+      get().updateNodeData(id, { needsRestart: false });
+    }
+  },
+  batchPause: async () => {
+    const ids = Array.from(get().selectedNodeIds);
+    await Promise.allSettled(ids.map((id) => api.post(`/workspaces/${id}/pause`)));
+  },
+  batchDelete: async () => {
+    const ids = Array.from(get().selectedNodeIds);
+    await Promise.allSettled(ids.map((id) => api.del(`/workspaces/${id}`)));
+    for (const id of ids) {
+      get().removeNode(id);
+    }
+    set({ selectedNodeIds: new Set<string>() });
+  },
   wsStatus: "connecting",
   setWsStatus: (status) => set({ wsStatus: status }),
   hydrationError: null,