Korjaa ticket_fetch ja sähköpostien duplikaattiongelma

- Korjaa implode()-bugi: $email['to'] on string, ei array
- Lisää fetched_message_ids-taulu joka estää poistettujen
  tikettien uudelleenluonnin seuraavassa haussa
- Viestit haetaan postilaatikosta vain kertaalleen

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

api.php

@@ -2906,8 +2906,9 @@ switch ($action) {
         $threadedCount = 0;
         $errors = [];
 
-        // Collect all existing message IDs for duplicate detection
-        $existingMsgIds = [];
+        // Collect all previously fetched message IDs (persists even after ticket deletion)
+        $existingMsgIds = dbGetFetchedMessageIds($companyId);
+        // Also include message IDs from current tickets (for backward compatibility)
         foreach ($tickets as $t) {
             if ($t['message_id']) $existingMsgIds[$t['message_id']] = true;
             foreach ($t['messages'] ?? [] as $m) {
@@ -3016,7 +3017,7 @@ switch ($action) {
                     ];
 
                     // Apply auto-rules
-                    $toAddresses = implode(' ', $email['to'] ?? []);
+                    $toAddresses = $email['to'] ?? '';
                     foreach ($rules as $rule) {
                         if (empty($rule['enabled'])) continue;
                         $match = true;
@@ -3094,7 +3095,11 @@ switch ($action) {
                     $newCount++;
                 }
 
-                if ($email['message_id']) $existingMsgIds[$email['message_id']] = true;
+                // Merkitse haetuksi pysyvästi
+                if ($email['message_id']) {
+                    dbMarkMessageIdFetched($companyId, $email['message_id']);
+                    $existingMsgIds[$email['message_id']] = true;
+                }
             }
         }