feat(web): workspace components — ComparePane, Memory page, McpDialog, error boundaries, message-parts

- Add ComparePane.tsx: side-by-side AI response comparison
- Add Memory.tsx: memory management page with CRUD UI
- Add McpPermissionDialog.tsx: MCP tool permission approval dialog
- Add McpResponseDisplay.tsx: MCP response visualization
- Add MessageBoundary.tsx + MessageListErrorBoundary.tsx: error resilience
- Add EmptyState.tsx: contextual empty state component
- Add KeyboardShortcutsDialog.tsx: keyboard shortcut reference
- Add message-parts/: ActionRow, CompactCard, MistakeRecoverySentinel, ReasoningBlock, SendToTerminalMenu, StatsLine, SummaryCard
- Add useDraftPersistence.ts: draft message persistence hook
- Add useTerminals.ts: terminal session management hook
- Add keyboard-shortcuts.ts + tool-utils.ts: shared utilities
- Extend components: ChatInput, MessageBubble, MessageList, Workspace, panes
- Extend hooks: useTerminalSocket, useSessionStream test suite
- Update pages: Home, Project — workspace layout and session flow

apps/web/src/components/message-parts/SendToTerminalMenu.tsx

@@ -0,0 +1,69 @@
+import { useState } from 'react';
+import type { ReactNode } from 'react';
+import { toast } from 'sonner';
+import { sendToTerminal } from '@/lib/events';
+import { useTerminals } from '@/hooks/useTerminals';
+import {
+  ContextMenu,
+  ContextMenuContent,
+  ContextMenuItem,
+  ContextMenuSeparator,
+  ContextMenuSub,
+  ContextMenuSubContent,
+  ContextMenuSubTrigger,
+  ContextMenuTrigger,
+} from '@/components/ui/context-menu';
+
+// Wrap a message body with a right-click context menu offering Copy and
+// "Send to terminal → <pane name>". Send is disabled when nothing is
+// selected or no terminal panes are open; clicking a target emits a
+// sendToTerminal event that TerminalPane subscribes to (filtered by pane_id).
+export function SendToTerminalMenu({ children }: { children: ReactNode }) {
+  const [selection, setSelection] = useState('');
+  const terminals = useTerminals();
+  const hasSelection = selection.length > 0;
+  const canSend = hasSelection && terminals.length > 0;
+
+  return (
+    <ContextMenu
+      onOpenChange={(open) => {
+        if (open) {
+          const sel = typeof window !== 'undefined' ? window.getSelection()?.toString() ?? '' : '';
+          setSelection(sel);
+        }
+      }}
+    >
+      <ContextMenuTrigger asChild>{children}</ContextMenuTrigger>
+      <ContextMenuContent>
+        <ContextMenuItem
+          disabled={!hasSelection}
+          onSelect={() => {
+            void navigator.clipboard.writeText(selection).catch((err) => {
+              toast.error(err instanceof Error ? err.message : 'copy failed');
+            });
+          }}
+        >
+          Copy
+        </ContextMenuItem>
+        <ContextMenuSeparator />
+        <ContextMenuSub>
+          <ContextMenuSubTrigger disabled={!canSend}>Send to terminal</ContextMenuSubTrigger>
+          <ContextMenuSubContent>
+            {terminals.length === 0 ? (
+              <ContextMenuItem disabled>No terminal panes open</ContextMenuItem>
+            ) : (
+              terminals.map((t) => (
+                <ContextMenuItem
+                  key={t.paneId}
+                  onSelect={() => sendToTerminal.emit({ pane_id: t.paneId, text: selection })}
+                >
+                  {t.label}
+                </ContextMenuItem>
+              ))
+            )}
+          </ContextMenuSubContent>
+        </ContextMenuSub>
+      </ContextMenuContent>
+    </ContextMenu>
+  );
+}