feat(reports): sales hasData existence flag (service + route)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/services/reports/sales.service.ts

@@ -1663,6 +1663,19 @@ async function fetchNewLeads(
   return { total, bySource };
 }
 
+/**
+ * Window-independent existence check: does this port have any interest at
+ * all? Drives the Sales report-level empty state.
+ */
+export async function salesHasData(portId: string): Promise<boolean> {
+  const rows = await db
+    .select({ one: sql<number>`1` })
+    .from(interests)
+    .where(eq(interests.portId, portId))
+    .limit(1);
+  return rows.length > 0;
+}
+
 // Re-export so the active-interest helper is available to callers that
 // want to add their own constraints layered onto the same predicate.
 export { activeInterestsWhere };