fix(imap-idle): use snake_case table + columns (match Prisma @map)

Daemon SQL used PascalCase "MailConnection" + camelCase column-names
that match the Prisma model field-names — but actual DB has snake_case
table "mail_connections" with snake_case columns (per @map decorators).

Result: daemon was online but ALL queries failed with
  relation "rebreak.MailConnection" does not exist
→ no mailboxes loaded → no IDLE-sessions established.

Fix: query "rebreak.mail_connections" with snake_case columns, alias
back to camelCase via SQL AS so rest of the daemon code works unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/imap-idle/index.mjs

@@ -44,11 +44,19 @@ const RECONNECT_LOOP_DELAY_MS = 60 * 1000;
 const pool = new pg.Pool({ connectionString: process.env.DATABASE_URL });
 
 async function loadActiveConnections() {
+  // DB-table heißt "mail_connections" + snake_case columns (Prisma @map).
+  // Aliase auf camelCase damit der restliche Daemon-Code unverändert bleibt.
   const { rows } = await pool.query(
-    `SELECT id, "userId", email, "imapHost", "imapPort",
-            "passwordEncrypted", "rejectUnauthorized", "useStarttls"
-     FROM rebreak."MailConnection"
-     WHERE "isActive" = true`,
+    `SELECT id,
+            user_id           AS "userId",
+            email,
+            imap_host         AS "imapHost",
+            imap_port         AS "imapPort",
+            password_encrypted AS "passwordEncrypted",
+            reject_unauthorized AS "rejectUnauthorized",
+            use_starttls      AS "useStarttls"
+     FROM rebreak.mail_connections
+     WHERE is_active = true`,
   );
   return rows;
 }