feat: add WorkflowBrowserModal and wire up Header open-project button

Header's folder icon now opens the workflow browser modal instead of
the OS directory picker directly. The modal wraps WorkflowBrowserView
in the standard overlay pattern.

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

src/components/Header.tsx

@@ -1,11 +1,12 @@
 "use client";
 
 import { useState, useMemo, useCallback } from "react";
-import { useWorkflowStore, WorkflowFile } from "@/store/workflowStore";
+import { useWorkflowStore } from "@/store/workflowStore";
 import { useShallow } from "zustand/shallow";
 import { ProjectSetupModal } from "./ProjectSetupModal";
 import { CostIndicator } from "./CostIndicator";
 import { KeyboardShortcutsDialog } from "./KeyboardShortcutsDialog";
+import { WorkflowBrowserModal } from "./WorkflowBrowserModal";
 
 function CommentsNavigationIcon() {
   // Subscribe to nodes so we re-render when comments change
@@ -93,6 +94,7 @@ export function Header() {
 
   const [showProjectModal, setShowProjectModal] = useState(false);
   const [projectModalMode, setProjectModalMode] = useState<"new" | "settings">("new");
+  const [showWorkflowBrowser, setShowWorkflowBrowser] = useState(false);
 
   const isProjectConfigured = !!workflowName;
   const canSave = !!(workflowId && workflowName && saveDirectoryPath);
@@ -114,36 +116,8 @@ export function Header() {
     setShowProjectModal(true);
   };
 
-  const handleOpenFile = async () => {
-    try {
-      // Open native OS directory picker
-      const browseRes = await fetch("/api/browse-directory");
-      const browseResult = await browseRes.json();
-
-      if (!browseResult.success || browseResult.cancelled || !browseResult.path) {
-        if (!browseResult.success && !browseResult.cancelled) {
-          alert(browseResult.error || "Failed to open directory picker");
-        }
-        return;
-      }
-
-      const dirPath = browseResult.path;
-
-      // Load workflow JSON from that directory
-      const loadRes = await fetch(`/api/workflow?path=${encodeURIComponent(dirPath)}&load=true`);
-      const loadResult = await loadRes.json();
-
-      if (!loadResult.success) {
-        alert(loadResult.error || "No workflow file found in directory");
-        return;
-      }
-
-      const workflow = loadResult.workflow as WorkflowFile;
-      await loadWorkflow(workflow, dirPath);
-    } catch (error) {
-      console.error("Failed to open workflow:", error);
-      alert("Failed to open workflow. Please try again.");
-    }
+  const handleOpenFile = () => {
+    setShowWorkflowBrowser(true);
   };
 
   const handleProjectSave = async (id: string, name: string, path: string) => {
@@ -230,6 +204,14 @@ export function Header() {
         onSave={handleProjectSave}
         mode={projectModalMode}
       />
+      <WorkflowBrowserModal
+        isOpen={showWorkflowBrowser}
+        onClose={() => setShowWorkflowBrowser(false)}
+        onWorkflowLoaded={async (workflow, dirPath) => {
+          setShowWorkflowBrowser(false);
+          await loadWorkflow(workflow, dirPath);
+        }}
+      />
       <header className="h-11 bg-neutral-900 border-b border-neutral-800 flex items-center justify-between px-4 shrink-0">
         <div className="flex items-center gap-2">
           <button

src/components/WorkflowBrowserModal.tsx

@@ -0,0 +1,36 @@
+"use client";
+
+import { WorkflowFile } from "@/store/workflowStore";
+import { WorkflowBrowserView } from "./quickstart/WorkflowBrowserView";
+
+interface WorkflowBrowserModalProps {
+  isOpen: boolean;
+  onClose: () => void;
+  onWorkflowLoaded: (workflow: WorkflowFile, directoryPath: string) => void;
+}
+
+export function WorkflowBrowserModal({
+  isOpen,
+  onClose,
+  onWorkflowLoaded,
+}: WorkflowBrowserModalProps) {
+  if (!isOpen) return null;
+
+  return (
+    <div
+      className="fixed inset-0 z-[100] flex items-center justify-center bg-black/60"
+      onWheelCapture={(e) => e.stopPropagation()}
+      onClick={onClose}
+    >
+      <div
+        className="w-full max-w-2xl mx-4 bg-neutral-800 rounded-xl border border-neutral-700 shadow-2xl overflow-clip max-h-[85vh] flex flex-col"
+        onClick={(e) => e.stopPropagation()}
+      >
+        <WorkflowBrowserView
+          onWorkflowLoaded={onWorkflowLoaded}
+          onClose={onClose}
+        />
+      </div>
+    </div>
+  );
+}