test: major coverage expansion — 18 new test files, ~830 new tests

Unit tests: 1354 → 1781 (+427)
- 11 new AI bridge module tests (packages/ai/ from 2/13 → 13/13 files)
- files-page-store (0% → full), pdf-to-image-store, features-store expanded
- saturation and edit-metadata image-engine operations
- analytics route, features route, web analytics lib, api-extended

Integration tests: ~2070 → 2320 (+250)
- 31 integration files expanded with branch-coverage-targeted tests
- progress.ts SSE endpoints (28% → comprehensive, +18 tests)
- gif-tools all modes (+18), pdf-to-image format variants (+13)
- Cross-format matrix expanded to 17 tools × 17 formats (467 tests)
- Adversarial: concurrent, memory pressure, unicode filenames, pipeline limits

E2E-Docker: +1020 lines across 6 spec files
- Info, colors, sharpening, base64, QR read, JXL/ICO/SVG formats
- Strip-metadata, image-enhancement, content-aware-resize expanded
- Batch pipelines, multi-format batches, HEIC input coverage

tests/integration/qr-generate.test.ts

@@ -406,6 +406,62 @@ describe("QR Generate", () => {
     expect(result.processedSize).toBeGreaterThan(0);
   });
 
+  it("handles very long text (approaching max 2000 chars)", async () => {
+    const longText = "A".repeat(2000);
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/qr-generate",
+      headers: {
+        authorization: `Bearer ${adminToken}`,
+        "content-type": "application/json",
+      },
+      payload: {
+        text: longText,
+      },
+    });
+
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+
+  it("rejects text exceeding max length (2001 chars)", async () => {
+    const tooLong = "A".repeat(2001);
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/qr-generate",
+      headers: {
+        authorization: `Bearer ${adminToken}`,
+        "content-type": "application/json",
+      },
+      payload: {
+        text: tooLong,
+      },
+    });
+
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("generates QR code at maximum allowed size (10000)", async () => {
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/qr-generate",
+      headers: {
+        authorization: `Bearer ${adminToken}`,
+        "content-type": "application/json",
+      },
+      payload: {
+        text: "max size test",
+        size: 10000,
+      },
+    });
+
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+
   it("generates QR with transparent background (3-char hex)", async () => {
     const res = await app.inject({
       method: "POST",