feat(renderer): Breadcrumb shows heading symbols (settings toggleable)

src/renderer/components/layout/Breadcrumb.tsx

@@ -1,7 +1,38 @@
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+import { useSettingsStore } from '@/stores/settings-store';
+
+function extractHeadings(content: string): { level: number; text: string }[] {
+  const lines = content.split('\n');
+  const headings: { level: number; text: string }[] = [];
+  for (const line of lines) {
+    const m = line.match(/^(#{1,6})\s+(.+)$/);
+    if (m) headings.push({ level: m[1].length, text: m[2].trim() });
+  }
+  return headings;
+}
+
 export function Breadcrumb() {
+  const activeTabId = useFileStore((s) => s.activeTabId);
+  const openTabs = useFileStore((s) => s.openTabs);
+  const buffer = useEditorStore((s) => (activeTabId ? s.buffers.get(activeTabId) : undefined));
+  const showSymbols = useSettingsStore((s) => s.breadcrumbSymbols);
+
+  const tab = activeTabId ? openTabs.find((t) => t.id === activeTabId) : null;
+  const headings = showSymbols && buffer ? extractHeadings(buffer.content).slice(0, 3) : [];
+
   return (
-    <nav aria-label="File path" className="flex h-7 items-center border-b border-border bg-card/10 px-3 text-xs text-muted-foreground">
-      <span>No file selected</span>
+    <nav
+      aria-label="File path"
+      className="flex h-7 items-center gap-1 border-b border-border bg-card/10 px-3 text-xs text-muted-foreground"
+    >
+      <span>{tab ? tab.title : 'No file selected'}</span>
+      {headings.map((h, i) => (
+        <span key={i} className="flex items-center gap-1">
+          <span aria-hidden="true">›</span>
+          <span className="truncate">{'#'.repeat(h.level)} {h.text}</span>
+        </span>
+      ))}
     </nav>
   );
 }

tests/component/layout/Breadcrumb.test.tsx

@@ -0,0 +1,50 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { Breadcrumb } from '@/components/layout/Breadcrumb';
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+import { useSettingsStore } from '@/stores/settings-store';
+
+describe('Breadcrumb', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useSettingsStore.setState({ ...useSettingsStore.getInitialState(), breadcrumbSymbols: true });
+    useFileStore.setState({ activeTabId: '/test.md', openTabs: [{ id: '/test.md', path: '/test.md', title: 'test.md', dirty: false }] } as any);
+    useEditorStore.setState({ buffers: new Map([['/test.md', { id: '/test.md', path: '/test.md', content: '# H1\n## H2', dirty: false }]]) } as any);
+  });
+
+  it('shows "No file selected" when no tab is active', () => {
+    useFileStore.setState({ activeTabId: null, openTabs: [] } as any);
+    render(<Breadcrumb />);
+    expect(screen.getByText('No file selected')).toBeInTheDocument();
+  });
+
+  it('shows tab title when a tab is active', () => {
+    render(<Breadcrumb />);
+    expect(screen.getByText('test.md')).toBeInTheDocument();
+  });
+
+  it('shows heading symbols when breadcrumbSymbols is true', () => {
+    render(<Breadcrumb />);
+    expect(screen.getByText('test.md')).toBeInTheDocument();
+    expect(screen.getByText(/# H1/)).toBeInTheDocument();
+  });
+
+  it('does not show heading symbols when breadcrumbSymbols is false', () => {
+    useSettingsStore.setState({ ...useSettingsStore.getInitialState(), breadcrumbSymbols: false });
+    render(<Breadcrumb />);
+    expect(screen.getByText('test.md')).toBeInTheDocument();
+    expect(screen.queryByText(/# H1/)).not.toBeInTheDocument();
+  });
+
+  it('limits heading symbols to 3', () => {
+    useFileStore.setState({ activeTabId: '/test.md', openTabs: [{ id: '/test.md', path: '/test.md', title: 'test.md', dirty: false }] } as any);
+    useEditorStore.setState({ buffers: new Map([['/test.md', { id: '/test.md', path: '/test.md', content: '# H1\n## H2\n### H3\n#### H4', dirty: false }]]) } as any);
+    render(<Breadcrumb />);
+    // Should show H1, H2, H3 but not H4
+    expect(screen.getByText(/# H1/)).toBeInTheDocument();
+    expect(screen.getByText(/# H2/)).toBeInTheDocument();
+    expect(screen.getByText(/# H3/)).toBeInTheDocument();
+    expect(screen.queryByText(/# H4/)).not.toBeInTheDocument();
+  });
+});