feat: live class sessions, CE workflow, and docs (#683)

Adds live-class session scheduling on lessons (join link, date/time,
timezone) with automatic 24h and 1h reminder emails plus a calendar
invite (.ics), a time-change notification with an updated invite, a
teacher-authored welcome email and session invite on enrollment, and a
"Notify students" quiz nudge.

LMS gets an upcoming live-sessions card and Join buttons, plus a
reusable live-session card component (3 states) in @cio/ui with a
Storybook story. The sidebar content tree now reflects sequential
progression locking like the content list, and the course-completion
confetti regression is fixed.

Org-based emails no longer reference ClassroomIO by name. Docs add
live-class, welcome-email, and course-progression guides, expand the
certificates guide (design, signatures, corrected labels), move
plan-required callouts to the top, flatten how-to-guides to the docs
root with redirects, and add screenshots. Includes an add-docs-image
skill.

packages/jobs/src/enqueue/index.ts

@@ -1,3 +1,4 @@
 export * from './media';
 export * from './emails';
 export * from './agent-course-generation';
+export * from './notifications';

packages/jobs/src/enqueue/notifications.ts

@@ -0,0 +1,51 @@
+import type { JobsOptions } from 'bullmq';
+
+import { JOB_NAMES, QUEUE_NAMES } from '../queues/names';
+import { QUEUE_DEFAULTS } from '../queues/defaults';
+import { getQueue } from '../queues/factories';
+import type { TNotifyCourseExercisePayload, TNotifyCourseSessionUpdatePayload } from '../payloads/notifications';
+
+/**
+ * Enqueue a `notifications:notify-course-exercise` job. Returns the BullMQ
+ * job id so the dashboard can poll its status. Each click is a fresh nudge,
+ * so we do NOT set a stable jobId (no dedupe across clicks).
+ */
+export async function enqueueNotifyCourseExercise(
+  payload: TNotifyCourseExercisePayload,
+  options: JobsOptions = {}
+): Promise<string | undefined> {
+  const job = await getQueue(QUEUE_NAMES.notifications).add(JOB_NAMES.notifications.notifyCourseExercise, payload, {
+    ...QUEUE_DEFAULTS[QUEUE_NAMES.notifications],
+    ...options
+  });
+
+  return job.id;
+}
+
+/** Enqueue a one-off run of the session-reminder scan (manual trigger / on-demand). */
+export async function enqueueSessionReminderScan(options: JobsOptions = {}): Promise<string | undefined> {
+  const job = await getQueue(QUEUE_NAMES.notifications).add(
+    JOB_NAMES.notifications.sessionReminderScan,
+    {},
+    { ...QUEUE_DEFAULTS[QUEUE_NAMES.notifications], ...options }
+  );
+
+  return job.id;
+}
+
+/** Enqueue a "session updated" notification that emails members an updated calendar invite. */
+export async function enqueueNotifyCourseSessionUpdate(
+  payload: TNotifyCourseSessionUpdatePayload,
+  options: JobsOptions = {}
+): Promise<string | undefined> {
+  const job = await getQueue(QUEUE_NAMES.notifications).add(
+    JOB_NAMES.notifications.notifyCourseSessionUpdate,
+    payload,
+    {
+      ...QUEUE_DEFAULTS[QUEUE_NAMES.notifications],
+      ...options
+    }
+  );
+
+  return job.id;
+}