feat(15-03): add bounded phishing sweep service

- sweepPhishingTickets() queries recently-modified tickets (7d window, LIMIT 500)
- delegates each ticket to shared detectPhishingTicket (no duplicated match/hash logic)
- per-row try/catch increments errors without aborting the loop

lib/services/phishing-sweep-service.ts

@@ -0,0 +1,101 @@
+/**
+ * Phishing Sweep Service
+ *
+ * Bounded cron reconciliation sweep over recently-modified tickets, mirroring
+ * ticket-reconciliation-service.ts's structure. The webhook path (Plan 03,
+ * webhook-service.ts) is the primary near-real-time trigger; this sweep
+ * catches anything the webhook missed (dropped events, backfilled tickets,
+ * tickets whose content changed after the webhook already fired) by
+ * re-running the same shared detectPhishingTicket core.
+ *
+ * No duplicated pattern-matching/hashing logic here — this file only
+ * queries candidate tickets and delegates detection to phishing-detector.ts.
+ */
+
+import { postgresClient } from './postgres-client';
+import { detectPhishingTicket, type DetectableTicket } from './phishing-detector';
+import { createSyncLogger } from '../utils/sync-logger';
+
+export interface PhishingSweepResult {
+  scanned: number;
+  flagged: number;
+  skippedUnchanged: number;
+  errors: number;
+}
+
+const SWEEP_WINDOW_DAYS = 7;
+const SCAN_LIMIT = 500;
+
+/**
+ * Re-scan up to SCAN_LIMIT recently-modified tickets through the shared
+ * phishing detector. Bounded and idempotent — safe to run on a recurring
+ * schedule alongside the webhook trigger.
+ */
+export async function sweepPhishingTickets(): Promise<PhishingSweepResult> {
+  const logger = createSyncLogger({ component: 'PhishingSweep' });
+  const startedAt = Date.now();
+  const result: PhishingSweepResult = {
+    scanned: 0,
+    flagged: 0,
+    skippedUnchanged: 0,
+    errors: 0,
+  };
+
+  const candidatesQuery = `
+    SELECT id, ticket_number, title, description, company_id, contact_id, created_by_contact_id
+      FROM tickets
+     WHERE is_deleted = false
+       AND last_activity_date > NOW() - INTERVAL '${SWEEP_WINDOW_DAYS} days'
+     ORDER BY last_activity_date DESC
+     LIMIT $1
+  `;
+  const candidates = await postgresClient.query<{
+    id: string;
+    ticket_number: string | null;
+    title: string | null;
+    description: string | null;
+    company_id: number | null;
+    contact_id: number | null;
+    created_by_contact_id: number | null;
+  }>(candidatesQuery, [SCAN_LIMIT]);
+
+  logger.info(
+    `Sweeping ${candidates.rows.length} recently-modified tickets (>${SWEEP_WINDOW_DAYS}d, limit=${SCAN_LIMIT})`
+  );
+
+  for (const row of candidates.rows) {
+    result.scanned += 1;
+    const ticket: DetectableTicket = {
+      id: Number(row.id),
+      ticket_number: row.ticket_number,
+      title: row.title,
+      description: row.description,
+      company_id: row.company_id,
+      contact_id: row.contact_id,
+      created_by_contact_id: row.created_by_contact_id,
+    };
+
+    try {
+      const detection = await detectPhishingTicket(ticket);
+      if (detection.skippedUnchanged) {
+        result.skippedUnchanged += 1;
+      } else if (detection.flagged) {
+        result.flagged += 1;
+      }
+    } catch (err) {
+      result.errors += 1;
+      logger.warn(
+        `Phishing detection failed for ticket ${ticket.id}`,
+        { ticketId: ticket.id },
+        err instanceof Error ? err : new Error(String(err))
+      );
+    }
+  }
+
+  logger.info(
+    `Phishing sweep complete: scanned=${result.scanned} flagged=${result.flagged} skippedUnchanged=${result.skippedUnchanged} errors=${result.errors}`,
+    { duration: Date.now() - startedAt }
+  );
+
+  return result;
+}