fix: wire conversation panel to DAG nodes with toggle support

- Add MessageSquare icon to GraphNodeCard; prop-thread onConversationOpen
  and selectedTaskId through WorkflowGraph node data (no useUrlState
  inside ReactFlow nodes — avoids context/timing issues)
- Fix ContextualRightPanel: check taskId before epicId so clicking the
  conversation icon always opens ThreadDrawer even when an epic filter
  is active
- setEpicId now clears task from URL so selecting an epic resets any
  open conversation thread
- handleGraphSelect toggles: second click on same node calls setTaskId(null)
  closing the right panel
- Add onSelect to WorkflowGraph flowModel deps to prevent stale callbacks
- Fix ContextualRightPanel onClose no-ops: wired to setTaskId(null) /
  setSwarmId(null) so back button works
- Right panel always visible (removed panel==='open' gate in UnifiedShell)
- SmartDag task grid: horizontal scroll, fixed-width cards, hideClosed=true
- Add <Suspense> in page.tsx for useSearchParams compatibility
- Enable dolt auto-start in .beads/config.yaml
- Add 14 static analysis tests (graph-node-conversation.test.tsx)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/hooks/use-url-state.ts

@@ -227,7 +227,8 @@ export function useUrlState(): UrlState {
   }, [updateUrl]);
 
   const setEpicId = useCallback((id: string | null) => {
-    updateUrl({ epic: id });
+    // Selecting an epic clears any active task conversation so SwarmCommandFeed shows
+    updateUrl({ epic: id, task: null });
   }, [updateUrl]);
 
   const togglePanel = toggleRightPanel;