Outline: share as a read-only link

- Share on the Outline page opens a sheet: create / copy / turn off a
  read-only link, share the link with the system share sheet, or send the
  outline as text
- The link has its own token (separate from the whole-study share link) and
  the public endpoint returns only the outlines, rebuilt field by field:
  no observations, interpretations, applications, scripts or word notes
- Opening the link shows the outline(s) with no sign-in, a switcher between
  the whole-study and per-chunk outlines, and Print / PDF
- New outline_share_token column (added automatically on start)

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

server/db.js

@@ -83,6 +83,10 @@ export function initDb() {
   if (!projectCols.some((c) => c.name === 'share_token')) {
     db.exec('ALTER TABLE projects ADD COLUMN share_token TEXT');
   }
+  if (!projectCols.some((c) => c.name === 'outline_share_token')) {
+    db.exec('ALTER TABLE projects ADD COLUMN outline_share_token TEXT');
+  }
+  db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_projects_outline_share_token ON projects(outline_share_token) WHERE outline_share_token IS NOT NULL');
   db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_projects_share_token ON projects(share_token) WHERE share_token IS NOT NULL');
 
   // Reader ink — one row per user + book + chapter, stored as JSON
@@ -414,6 +418,28 @@ export function clearShareToken(id, userId) {
   db.prepare('UPDATE projects SET share_token = NULL WHERE id = ? AND user_id = ?').run(id, userId);
 }
 
+// ---- read-only outline links: a separate token, so sharing an outline never shares the whole study ----
+
+export function getOutlineShareToken(id, userId) {
+  const row = db.prepare('SELECT outline_share_token AS t FROM projects WHERE id = ? AND user_id = ?').get(id, userId);
+  return row?.t ?? null;
+}
+
+export function setOutlineShareToken(id, userId, token) {
+  return db.prepare('UPDATE projects SET outline_share_token = ? WHERE id = ? AND user_id = ?').run(token, id, userId).changes > 0;
+}
+
+export function clearOutlineShareToken(id, userId) {
+  db.prepare('UPDATE projects SET outline_share_token = NULL WHERE id = ? AND user_id = ?').run(id, userId);
+}
+
+/** Public lookup: the project data behind an outline link (callers must only ever send the outlines on). */
+export function getProjectByOutlineToken(token) {
+  const row = db.prepare('SELECT data FROM projects WHERE outline_share_token = ?').get(token);
+  if (!row) return null;
+  try { return JSON.parse(row.data); } catch { return null; }
+}
+
 /** Public lookup: returns the full project data for a valid share token, or null. No ownership check — this is the point. */
 export function getProjectByShareToken(token) {
   const row = db.prepare('SELECT data FROM projects WHERE share_token = ?').get(token);