Lisää Zammad-integraatio ja modulaarinen integraatiot-hallinta

- Uusi integrations-taulu tietokantaan (moduulimalli: type, enabled, config)
- ZammadClient-luokka: tiketit, artikkelit, vastaukset, ryhmät
- API-endpointit: integration_save, integration_test, zammad_sync, zammad_reply, zammad_groups
- Synkronointi: Zammad-tiketit → intran tiketit, artikkelit → viestit
- Vastaukset: Zammad-tiketteihin vastaus kulkee Zammad API:n kautta (→ O365)
- UI: Integraatiot-osio API-välilehdellä, toggle-kytkimet, Zammad-konfiguraatio
- tickets.zammad_ticket_id ja ticket_messages.zammad_article_id linkitys

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

db.php

@@ -602,6 +602,19 @@ function initDatabase(): void {
             FOREIGN KEY (laitetila_id) REFERENCES laitetilat(id) ON DELETE CASCADE,
             INDEX idx_laitetila (laitetila_id)
         ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4",
+
+        "CREATE TABLE IF NOT EXISTS integrations (
+            id VARCHAR(20) PRIMARY KEY,
+            company_id VARCHAR(50) NOT NULL,
+            type VARCHAR(50) NOT NULL,
+            enabled BOOLEAN DEFAULT FALSE,
+            config JSON,
+            created DATETIME,
+            updated DATETIME,
+            FOREIGN KEY (company_id) REFERENCES companies(id) ON DELETE CASCADE,
+            UNIQUE KEY uk_company_type (company_id, type),
+            INDEX idx_company (company_id)
+        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4",
     ];
 
     foreach ($tables as $i => $sql) {
@@ -644,6 +657,8 @@ function initDatabase(): void {
         "ALTER TABLE ticket_rules ADD COLUMN enabled BOOLEAN DEFAULT TRUE AFTER auto_close_days",
         "ALTER TABLE ticket_rules ADD COLUMN set_priority VARCHAR(20) DEFAULT '' AFTER type_set",
         "ALTER TABLE ticket_rules ADD COLUMN set_tags VARCHAR(255) DEFAULT '' AFTER set_priority",
+        "ALTER TABLE tickets ADD COLUMN zammad_ticket_id INT DEFAULT NULL AFTER mailbox_id",
+        "ALTER TABLE ticket_messages ADD COLUMN zammad_article_id INT DEFAULT NULL AFTER message_id",
     ];
     foreach ($alters as $sql) {
         try { $db->query($sql); } catch (\Throwable $e) { /* sarake on jo olemassa / jo ajettu */ }
@@ -2223,3 +2238,42 @@ function dbUpdateConnection(int $connectionId, array $data): void {
         $connectionId
     ]);
 }
+
+// ==================== INTEGRAATIOT ====================
+
+function dbLoadIntegrations(string $companyId): array {
+    return _dbFetchAll("SELECT * FROM integrations WHERE company_id = ? ORDER BY type", [$companyId]);
+}
+
+function dbGetIntegration(string $companyId, string $type): ?array {
+    $row = _dbFetchRow("SELECT * FROM integrations WHERE company_id = ? AND type = ?", [$companyId, $type]);
+    if ($row && $row['config']) {
+        $row['config'] = json_decode($row['config'], true) ?: [];
+    }
+    return $row;
+}
+
+function dbSaveIntegration(string $companyId, string $type, bool $enabled, array $config): void {
+    $existing = _dbFetchRow("SELECT id FROM integrations WHERE company_id = ? AND type = ?", [$companyId, $type]);
+    $now = date('Y-m-d H:i:s');
+    if ($existing) {
+        _dbExecute(
+            "UPDATE integrations SET enabled = ?, config = ?, updated = ? WHERE company_id = ? AND type = ?",
+            [$enabled ? 1 : 0, json_encode($config), $now, $companyId, $type]
+        );
+    } else {
+        $id = substr(uniqid(), -8) . bin2hex(random_bytes(2));
+        _dbExecute(
+            "INSERT INTO integrations (id, company_id, type, enabled, config, created, updated) VALUES (?, ?, ?, ?, ?, ?, ?)",
+            [$id, $companyId, $type, $enabled ? 1 : 0, json_encode($config), $now, $now]
+        );
+    }
+}
+
+function dbGetTicketByZammadId(string $companyId, int $zammadId): ?array {
+    return _dbFetchRow("SELECT * FROM tickets WHERE company_id = ? AND zammad_ticket_id = ?", [$companyId, $zammadId]);
+}
+
+function dbGetMessageByZammadArticleId(string $ticketId, int $articleId): ?array {
+    return _dbFetchRow("SELECT * FROM ticket_messages WHERE ticket_id = ? AND zammad_article_id = ?", [$ticketId, $articleId]);
+}