Add study templates, exports, breadcrumb, whole-Bible search, bookmarks UX, and share links

- Study templates: richer multi-line guiding questions in the OIA placeholders
- PDF/print export: reuses buildExportHtml in a new tab + window.print()
- Markdown export: new buildMarkdownExport() with matching tests
- Breadcrumb: current chunk's passage reference shown in the Study page header
- Reader bookmarks: SVG icons instead of ambiguous emoji, always visible
  (not hover-only, so it works on touch devices), plus a Bookmarks panel
  that lists all saved verses across every book and jumps + scrolls to them
- Whole-Bible search: no server-side search endpoint exists, so this fetches
  the full translation once (~7MB) and searches an in-memory flat verse
  index client-side, with results linking back into the reader
- Read-only share links: per-project share token, a public unauthenticated
  /api/share/:token endpoint, and a ?share=TOKEN view that bypasses the auth
  gate entirely and renders the export HTML in a script-sandboxed iframe

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/utils.test.js

@@ -7,6 +7,7 @@ import {
   parseBibleChapter,
   wordTableHtml,
   buildExportHtml,
+  buildMarkdownExport,
   buildClaudePrompt,
   createParagraphsFromText,
   migrateChunk,
@@ -469,6 +470,46 @@ describe('buildExportHtml', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// buildMarkdownExport
+// ---------------------------------------------------------------------------
+describe('buildMarkdownExport', () => {
+  test('includes the project title and translation as Markdown headers', () => {
+    const md = buildMarkdownExport(baseProject);
+    expect(md).toContain('# Titus 1 Study');
+    expect(md).toContain('*BSB*');
+  });
+
+  test('includes a chapter heading and chunk reference', () => {
+    const md = buildMarkdownExport(baseProject);
+    expect(md).toContain('## Titus 1');
+    expect(md).toContain('### Titus 1:1-2');
+  });
+
+  test('includes verse text and OIA notes', () => {
+    const md = buildMarkdownExport(baseProject);
+    expect(md).toContain('Paul, a servant of God.');
+    expect(md).toContain('Key observations.');
+    expect(md).toContain('Theological meaning.');
+    expect(md).toContain('Live it out.');
+  });
+
+  test('includes cross-references and Greek word data', () => {
+    const md = buildMarkdownExport(baseProject);
+    expect(md).toContain('John 1:1');
+    expect(md).toContain('G1401');
+    expect(md).toContain('δοῦλος');
+  });
+
+  test('shows placeholder text when observation is empty', () => {
+    const project = {
+      ...baseProject,
+      chapters: [{ ...baseProject.chapters[0], chunks: [{ ...baseChunk, observation: '', interpretation: '', application: '' }] }],
+    };
+    expect(buildMarkdownExport(project)).toContain('_No observation._');
+  });
+});
+
 // ---------------------------------------------------------------------------
 // createParagraphsFromText
 // ---------------------------------------------------------------------------