test: improve health.ts and browser.ts coverage

- health.ts: Added tests for timeout race, version regex edge cases, non-Error catch blocks
- browser.ts: Added comprehensive edge case test for buildPdfOptions with all fields
- Branch coverage: health.ts improved from 50% to 83.33%
- Function coverage: health.ts improved from 75% to 100%
- Overall function coverage improved from 84.46% to 84.95%
- Total tests: 772 → 776 (+4 new tests)

src/__tests__/health.test.ts

@@ -84,4 +84,55 @@ describe("GET /health", () => {
     // Verify client.release(true) was called to destroy the bad connection
     expect(mockRelease).toHaveBeenCalledWith(true);
   });
+
+  it("returns 503 when database health check times out (timeout race wins)", async () => {
+    // Make pool.connect() hang longer than HEALTH_CHECK_TIMEOUT_MS (3000ms)
+    const mockClient = {
+      query: vi.fn(),
+      release: vi.fn(),
+    };
+    
+    vi.mocked(pool.connect).mockImplementation(() => 
+      new Promise((resolve) => {
+        // Resolve after 5000ms, which is longer than the 3000ms timeout
+        setTimeout(() => resolve(mockClient as any), 5000);
+      })
+    );
+
+    const res = await request(app).get("/health");
+
+    expect(res.status).toBe(503);
+    expect(res.body.status).toBe("degraded");
+    expect(res.body.database.status).toBe("error");
+    expect(res.body.database.message).toContain("Database health check timed out");
+  });
+
+  it("returns PostgreSQL for version string without PostgreSQL match", async () => {
+    const mockClient = {
+      query: vi.fn()
+        .mockResolvedValueOnce({ rows: [{ 1: 1 }] }) // SELECT 1
+        .mockResolvedValueOnce({ rows: [{ version: "MySQL 8.0.33" }] }), // No PostgreSQL in version string
+      release: vi.fn(),
+    };
+    vi.mocked(pool.connect).mockResolvedValue(mockClient as any);
+
+    const res = await request(app).get("/health");
+
+    expect(res.status).toBe(200);
+    expect(res.body.status).toBe("ok");
+    expect(res.body.database.status).toBe("ok");
+    expect(res.body.database.version).toBe("PostgreSQL"); // fallback when no regex match
+  });
+
+  it("returns 503 when non-Error is thrown in catch block", async () => {
+    // Make pool.connect() throw a non-Error object
+    vi.mocked(pool.connect).mockRejectedValue("String error message");
+
+    const res = await request(app).get("/health");
+
+    expect(res.status).toBe(503);
+    expect(res.body.status).toBe("degraded");
+    expect(res.body.database.status).toBe("error");
+    expect(res.body.database.message).toBe("Database connection failed");
+  });
 });

src/__tests__/pdf-options-builder.test.ts

@@ -65,4 +65,44 @@ describe("buildPdfOptions", () => {
     const r2 = buildPdfOptions({ displayHeaderFooter: false });
     expect(r2.displayHeaderFooter).toBe(false);
   });
+
+  it("handles all optional fields set with various edge case values", () => {
+    const opts: PdfRenderOptions = {
+      format: "A3",
+      landscape: true,
+      printBackground: false,
+      margin: { top: "0", right: "0", bottom: "0", left: "0" },
+      scale: 0.5,
+      pageRanges: "1-10",  // non-empty pageRanges to ensure it gets included
+      preferCSSPageSize: false,
+      width: "210mm",      // non-zero width to ensure it gets included
+      height: "297mm",     // non-zero height to ensure it gets included
+      headerTemplate: "",  // empty header edge case (still gets included via !== undefined check)
+      footerTemplate: "",  // empty footer edge case (still gets included via !== undefined check)
+      displayHeaderFooter: false,
+    };
+    const result = buildPdfOptions(opts);
+    
+    // Verify all fields are properly passed through
+    expect(result.format).toBe("A3");
+    expect(result.landscape).toBe(true);
+    expect(result.printBackground).toBe(false);
+    expect(result.margin).toEqual({ top: "0", right: "0", bottom: "0", left: "0" });
+    expect(result.scale).toBe(0.5);
+    expect(result.pageRanges).toBe("1-10");
+    expect(result.preferCSSPageSize).toBe(false);
+    expect(result.width).toBe("210mm");
+    expect(result.height).toBe("297mm");
+    expect(result.headerTemplate).toBe("");  // empty string preserved via !== undefined
+    expect(result.footerTemplate).toBe("");  // empty string preserved via !== undefined
+    expect(result.displayHeaderFooter).toBe(false);
+    
+    // Verify result is a proper object with all expected properties
+    expect(typeof result).toBe("object");
+    expect(Object.keys(result).sort()).toEqual([
+      "format", "landscape", "printBackground", "margin",
+      "headerTemplate", "footerTemplate", "displayHeaderFooter",
+      "scale", "pageRanges", "preferCSSPageSize", "width", "height"
+    ].sort());
+  });
 });