Teaching: hide-notes-until share, session length check, slides export

- A study share link can hide the owner's notes until a chosen time: the server
  sends only passages and discussion questions until then, with a banner in the
  shared view (new share_reveal column, migrated on start).
- Outline: a session length with "N of M min planned, X min over" and a marker
  on the point where the plan runs past it.
- Export > Slides: printable 16:9 slides (title, passage, outline points with
  their verse, discussion questions) for one session or all; light or dark.

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

src/pages/ExportPage.jsx

@@ -1,6 +1,7 @@
 // The Export stage: take the finished study out as a file, or share it read-only.
 import { useApp } from '../context/AppContext.js';
 import { useShareLink } from '../hooks/useShareLink.js';
+import SlidesExport from '../components/SlidesExport.jsx';
 import ImportNotes from '../components/ImportNotes.jsx';
 import HandoutExport from '../components/HandoutExport.jsx';
 import SessionSchedule from '../components/SessionSchedule.jsx';
@@ -53,7 +54,7 @@ export default function ExportPage() {
                   className="min-w-0 flex-1 truncate rounded-lg border border-[var(--r-line)] bg-[var(--r-bg)] px-3 py-2 text-xs text-[var(--r-sub)]" />
                 <button type="button" onClick={share.copy} className="shrink-0 rounded-lg bg-[var(--r-accent)] px-4 py-2 text-xs font-medium text-[var(--r-on)]">{share.shareCopied ? 'Copied!' : 'Copy'}</button>
               </div>
-              <LinkRules expiresAt={share.expiresAt} hasPasscode={share.hasPasscode} busy={share.shareBusy} onSave={share.enable} />
+              <LinkRules expiresAt={share.expiresAt} hasPasscode={share.hasPasscode} busy={share.shareBusy} onSave={share.enable} showReveal revealAt={share.revealAt} />
               {share.shareError && <p role="alert" className="text-xs text-[var(--r-danger,#b42318)]">{share.shareError}</p>}
               <button type="button" onClick={share.revoke} disabled={share.shareBusy} className="text-xs text-[var(--r-danger,#b42318)] hover:underline">{share.shareBusy ? 'Revoking…' : 'Revoke link'}</button>
             </div>
@@ -64,6 +65,8 @@ export default function ExportPage() {
 
         <HandoutExport project={project} />
 
+        <SlidesExport project={project} />
+
         <ImportNotes />
 
         <SessionSchedule project={project} />

src/pages/OutlinePage.jsx

@@ -11,12 +11,13 @@ import { buildChapterSummary } from '../utils/projectStorage.js';
 import { compactPassages } from '../utils/passageSummary.js';
 import { attachableFromChunk, fetchPassageText } from '../utils/passageText.js';
 import PresentMode from '../components/PresentMode.jsx';
+import { firstOverPoint, outlineSteps, planStatus } from '../utils/present.js';
 import IqOutlineAttach from '../components/iq/IqOutlineAttach.jsx';
 import ShareOutlineSheet from '../components/ShareOutlineSheet.jsx';
 import { downloadOutlineDocx, downloadOutlineMarkdown, printOutline } from '../utils/outlineExport.js';
 import {
   KINDS, STUDY, buildChunkFromNotes, buildFromNotes, notesBuildCount, addAfter, addChild, addRoot, chunkOf, countNodes, flatten, getNode, indent, insertAt, kindLabel, locate,
-  moveNode, newNode, outdent, outlineFor, outlineToText, removeNode, seedFromChunks, seedFromVerses, timeSummary, updateNode, withOutline,
+  moveNode, newNode, outdent, outlineFor, outlineToText, removeNode, seedFromChunks, seedFromVerses, timeSummary, totalMinutes, updateNode, withOutline,
 } from '../utils/outline.js';
 
 const iconBtn = 'flex h-7 w-7 items-center justify-center rounded-md text-sm text-[var(--r-sub)] hover:bg-black/5 hover:text-[var(--r-text)] disabled:opacity-30 disabled:hover:bg-transparent';
@@ -45,6 +46,11 @@ export default function OutlinePage() {
   const scopeChunk = scope === STUDY ? null : chunkOf(project, scope);
   const tree = outlineFor(project, scope);
   const rows = flatten(tree);
+  // The time you have for a session, and how the planned minutes measure up to it
+  const sessionMinutes = Number(project?.sessionMinutes) || 0;
+  const plan = planStatus(totalMinutes(tree), sessionMinutes);
+  const overPoint = firstOverPoint(outlineSteps(tree), sessionMinutes);
+  const setSessionMinutes = (value) => updateProject((current) => ({ ...current, sessionMinutes: value === '' ? null : Math.max(0, Math.min(600, Math.round(Number(value)))) }));
   const [pendingFocus, setPendingFocus] = useState(null);
   const [metaOpen, setMetaOpen] = useState(() => new Set()); // points whose detail fields are showing
   const [shareOpen, setShareOpen] = useState(false);
@@ -160,6 +166,11 @@ export default function OutlinePage() {
             </select>
           </label>
           {timeSummary(tree) && <span className="text-sm text-[var(--r-sub)]">{timeSummary(tree)}</span>}
+          <label className="flex items-center gap-1.5 text-sm text-[var(--r-sub)]">Session length
+            <input type="number" min="0" max="600" inputMode="numeric" aria-label="Session length in minutes" value={project?.sessionMinutes ?? ''} onChange={(e) => setSessionMinutes(e.target.value)}
+              className="w-16 rounded-lg border border-[var(--r-line)] bg-[var(--r-bg)] px-2 py-1 text-sm text-[var(--r-text)] focus:outline-none" /> min
+          </label>
+          {plan.state !== 'unset' && <span role="status" className={`text-sm ${plan.state === 'over' ? 'font-medium text-[var(--r-danger,#b42318)]' : 'text-[var(--r-sub)]'}`}>{plan.text}</span>}
           {scopeChunk && <button type="button" onClick={() => openChunk(scope)} className="text-sm text-[var(--r-accent)] hover:underline">Open this chunk in Study</button>}
         </div>
 
@@ -229,10 +240,11 @@ export default function OutlinePage() {
                       />
 
                       {/* What the point carries, at a glance */}
-                      {(node.kind || mins || node.ref || linked) && (
+                      {(node.kind || mins || node.ref || linked || overPoint?.id === node.id) && (
                         <p className="flex flex-wrap items-center gap-x-2 gap-y-1 px-2 text-xs text-[var(--r-sub)]">
                           {node.kind && <span className={`${chip} border-[var(--r-accent)] text-[var(--r-accent)]`}>{kindLabel(node.kind)}</span>}
                           {mins && <span>{node.minutes} min</span>}
+                          {overPoint?.id === node.id && <span className="font-medium text-[var(--r-danger,#b42318)]">Runs past {sessionMinutes} min here</span>}
                           {node.ref && <span>{node.ref}</span>}
                           {linked && node.chunkId !== scope && <button type="button" onClick={() => openChunk(node.chunkId)} className="text-[var(--r-accent)] hover:underline">Open chunk in Study</button>}
                         </p>