fix(fanavaran): select latest active policy by end date

Why:
- Fanavaran policy inquiry response order is inconsistent, so selecting the last item can choose an old or expired policy.

Changes:
- Select the policy with the latest Jalali EndDate.
- Reject empty policy responses, expired latest policies, and latest policies without a valid PolicyId.
- Stop Fanavaran submission when PolicyId cannot be resolved.

Impact:
- Fanavaran submit now fails clearly instead of continuing with PolicyId: null.

src/claim-request-management/fanavaran-policy-selection.spec.ts

@@ -0,0 +1,63 @@
+import { BadRequestException } from "@nestjs/common";
+import { selectLatestActiveFanavaranPolicy } from "./fanavaran-policy-selection";
+
+describe("selectLatestActiveFanavaranPolicy", () => {
+  const today = "2026-06-30";
+
+  it("selects the policy with the latest EndDate when newest is first", () => {
+    const selected = selectLatestActiveFanavaranPolicy(
+      [
+        { PolicyId: 4826286, EndDate: "1405/09/23" },
+        { PolicyId: 3719458, EndDate: "1404/09/06" },
+        { PolicyId: 2800731, EndDate: "1403/09/05" },
+      ],
+      today,
+    );
+
+    expect(selected.policyId).toBe(4826286);
+    expect(selected.endDate).toBe("1405/09/23");
+  });
+
+  it("selects the policy with the latest EndDate when newest is last", () => {
+    const selected = selectLatestActiveFanavaranPolicy(
+      [
+        { PolicyId: 2800731, EndDate: "1403/09/05" },
+        { PolicyId: 3719458, EndDate: "1404/09/06" },
+        { PolicyId: 4826286, EndDate: "1405/09/23" },
+      ],
+      today,
+    );
+
+    expect(selected.policyId).toBe(4826286);
+  });
+
+  it("rejects when no policies are returned", () => {
+    expect(() => selectLatestActiveFanavaranPolicy([], today)).toThrow(
+      BadRequestException,
+    );
+  });
+
+  it("rejects when the latest policy is expired", () => {
+    expect(() =>
+      selectLatestActiveFanavaranPolicy(
+        [
+          { PolicyId: 3719458, EndDate: "1404/09/06" },
+          { PolicyId: 2800731, EndDate: "1403/09/05" },
+        ],
+        today,
+      ),
+    ).toThrow(BadRequestException);
+  });
+
+  it("rejects when the latest policy has no valid PolicyId", () => {
+    expect(() =>
+      selectLatestActiveFanavaranPolicy(
+        [
+          { PolicyId: 3719458, EndDate: "1404/09/06" },
+          { PolicyId: null, EndDate: "1405/09/23" },
+        ],
+        today,
+      ),
+    ).toThrow(BadRequestException);
+  });
+});