email: push new-mail to /email via SSE (IMAP IDLE -> sidecar -> server -> EventSource)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/sidecar/email/email-idle.ts

@@ -25,6 +25,7 @@ const RECONCILE_MS = 5 * 60_000;
 
 const watchers = new Map<number, Watcher>();
 let reconcileTimer: ReturnType<typeof setInterval> | null = null;
+let notifyNewMail: ((userEmail: string) => void) | null = null;
 
 async function resolveAuth(account: Account): Promise<{ user: string; pass?: string; accessToken?: string } | null> {
   if (account.authType === 'oauth') {
@@ -46,7 +47,10 @@ async function runSync(w: Watcher): Promise<void> {
     const user = await getUserById(w.account.userId);
     if (!user) return;
     const result = await performResync({ accountId: w.account.id, userEmail: user.email, userId: user.id });
-    if (result.saved > 0) console.log(`[email-idle] ${w.account.email}: ${result.saved} new`);
+    if (result.saved > 0) {
+      console.log(`[email-idle] ${w.account.email}: ${result.saved} new`);
+      notifyNewMail?.(user.email);
+    }
   } catch (err) {
     console.error(`[email-idle] sync failed for ${w.account.email}:`, err instanceof Error ? err.message : err);
   } finally {
@@ -141,8 +145,9 @@ async function reconcile(): Promise<void> {
   }
 }
 
-export function initEmailIdle(): void {
+export function initEmailIdle(onNewMail?: (userEmail: string) => void): void {
   if (reconcileTimer) return;
+  notifyNewMail = onNewMail ?? null;
   console.log('[email-idle] starting IMAP IDLE watchers');
   setTimeout(() => void reconcile(), 5_000);
   reconcileTimer = setInterval(() => void reconcile(), RECONCILE_MS);

src/servers/sidecar/email/index.ts

@@ -85,8 +85,9 @@ const connection = createSidecarConnector({
   onConnected() {
     // Start email cron once connected (so queue commands can reach API server)
     initEmailCron();
-    // Real-time push via IMAP IDLE; the cron above is the slow backstop.
-    initEmailIdle();
+    // Real-time push via IMAP IDLE; the cron above is the slow backstop. On new mail, tell the API
+    // server so it can push an SSE event to that user's open /email page.
+    initEmailIdle((userEmail) => connection.send({ type: 'email:new', userEmail }));
   },
 });