Extract project header, share link, exports, and auth status

- ProjectHeader component replaces the headerButtons JSX in context; it
  owns the export menu and share panel state.
- useShareLink (share status/enable/revoke/copy) and useSharedView
  (?share= read-only view, now used directly by the router).
- utils/projectExport: HTML/Markdown/DOCX download and print-to-PDF.
- AuthStatus component replaces the authStatus JSX in context.
- Pages import wordStudy helpers directly instead of via context.
- Remove dead copyPronunciationGuide (PronunciationPage has its own).
- Tests: Markdown export, enabling a share link, the ?share= view.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/utils/projectExport.js

@@ -0,0 +1,49 @@
+// File exports of a study project: HTML, Markdown, DOCX, and print-to-PDF.
+import { buildExportHtml } from './bibleUtils.jsx';
+import { buildMarkdownExport } from './exportBuilders.js';
+import { buildChapterSummary } from './projectStorage.js';
+
+function downloadBlob(blob, filename) {
+  const url = URL.createObjectURL(blob);
+  const link = document.createElement('a');
+  link.href = url;
+  link.download = filename;
+  document.body.appendChild(link);
+  link.click();
+  document.body.removeChild(link);
+  URL.revokeObjectURL(url);
+}
+
+const fileBase = (project) => `${project.title.replace(/\s+/g, '-')}-study`;
+
+export function exportProjectHtml(project) {
+  const html = buildExportHtml(project);
+  downloadBlob(new Blob([html], { type: 'text/html;charset=utf-8' }), `${fileBase(project)}.html`);
+}
+
+export function exportProjectMarkdown(project) {
+  const markdown = buildMarkdownExport(project);
+  downloadBlob(new Blob([markdown], { type: 'text/markdown;charset=utf-8' }), `${fileBase(project)}.md`);
+}
+
+export async function exportProjectDocx(project) {
+  // docx is large, so it's only downloaded when someone actually exports.
+  const { buildStudyDocxBlob } = await import('./docxExport.js');
+  const blob = await buildStudyDocxBlob(project, buildChapterSummary(project));
+  downloadBlob(blob, `${fileBase(project)}.docx`);
+}
+
+export function printProjectPdf(project) {
+  const html = buildExportHtml(project);
+  const printWindow = window.open('', '_blank');
+  if (!printWindow) {
+    alert('Please allow pop-ups for this site to print or save as PDF.');
+    return;
+  }
+  printWindow.document.write(html);
+  printWindow.document.close();
+  printWindow.onload = () => {
+    printWindow.focus();
+    printWindow.print();
+  };
+}