Guard startup scheduler calls against unhandled promise rejections; v2.0.42

Replace bare `void fn()` with `fn().catch(err => console.error(...))` for all
four startup-time scheduler invocations so an unexpected rejection cannot
crash the Node.js process (which exits on unhandled rejections in v15+).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "2.0.41",
+  "version": "2.0.42",
   "type": "module",
   "scripts": {
     "dev": "vite",

server.js

@@ -191,7 +191,9 @@ Promise.all([
         console.error('[study-reminders] failed to schedule reminders:', err)
       })
     }, 60 * 60 * 1000)
-    void scheduleStudyReminders(sendStudyReminderEmail)
+    scheduleStudyReminders(sendStudyReminderEmail).catch(err => {
+      console.error('[study-reminders] failed to schedule reminders:', err)
+    })
 
     // Send re-engagement emails to inactive study users every hour
     setInterval(() => {
@@ -199,7 +201,9 @@ Promise.all([
         console.error('[study-reengagement] failed to schedule emails:', err)
       })
     }, 60 * 60 * 1000)
-    void scheduleReengagementEmails(sendStudyReengagementEmail)
+    scheduleReengagementEmails(sendStudyReengagementEmail).catch(err => {
+      console.error('[study-reengagement] failed to schedule emails:', err)
+    })
 
     // Send weekly lesson digest emails every hour (only actually fires every 7 days per user)
     setInterval(() => {
@@ -207,7 +211,9 @@ Promise.all([
         console.error('[study-digest] failed to schedule weekly digest:', err)
       })
     }, 60 * 60 * 1000)
-    void scheduleWeeklyDigestEmails(sendStudyWeeklyDigestEmail)
+    scheduleWeeklyDigestEmails(sendStudyWeeklyDigestEmail).catch(err => {
+      console.error('[study-digest] failed to schedule weekly digest:', err)
+    })
 
     // Check for a scheduled series transition every hour
     setInterval(() => {
@@ -215,7 +221,9 @@ Promise.all([
         console.error('[series-scheduler] error:', err)
       })
     }, 60 * 60 * 1000)
-    void runScheduledSeriesTransition()
+    runScheduledSeriesTransition().catch(err => {
+      console.error('[series-scheduler] error:', err)
+    })
 
     app.listen(PORT, () => {
       logResendEmailAlignmentWarnings()