test: expand API and GUI test coverage across all tools

Add ~500 new E2E tests and ~300 new integration tests covering:

- 24 new GUI E2E specs: navigation, responsive layout, keyboard shortcuts,
  tool UI for all 35 non-AI tools, batch/pipeline workflows, settings/RBAC,
  visual regression, accessibility, and performance budgets
- 3 new E2E-Docker specs: batch workflows, advanced pipelines, cross-format
- 1 new adversarial integration test: memory pressure, corrupted files,
  unicode filenames, extreme dimensions, pipeline/batch edge cases
- 29 expanded integration test files: HEIC/HEIF input, large files, parameter
  boundaries, batch processing, format edge cases across all tools
- Cross-format matrix expanded: 641 tests covering every tool x 18 formats
- AI bridge unit tests expanded: lifecycle, tool modules, error propagation
- Unit test gaps filled: analytics, tool-registry, web stores

Also fixes:
- vitest.config.ts: exclude e2e-docs and e2e-landing from Vitest runner
- AI E2E specs: add sidecar health check to skip gracefully when Python
  AI backend is not running instead of timing out

tests/unit/ai/ocr.test.ts

@@ -265,5 +265,78 @@ describe("extractText", () => {
         expect.objectContaining({ onProgress }),
       );
     });
+
+    it("omits onProgress when not provided", async () => {
+      await extractText(FAKE_INPUT, FAKE_OUTPUT_DIR);
+
+      const options = vi.mocked(runPythonWithProgress).mock.calls[0][2];
+      expect(options.onProgress).toBeUndefined();
+    });
+  });
+
+  describe("image downscaling", () => {
+    it("caps input to 2048px using resize with inside fit", async () => {
+      const resizeFn = vi.fn().mockReturnThis();
+      vi.mocked(sharp).mockImplementation(
+        () =>
+          ({
+            resize: resizeFn,
+            png: vi.fn().mockReturnThis(),
+            toBuffer: vi.fn().mockResolvedValue(Buffer.from("mock-png-data")),
+            metadata: vi.fn().mockResolvedValue({ width: 800, height: 600 }),
+          }) as unknown as ReturnType<typeof sharp>,
+      );
+
+      await extractText(FAKE_INPUT, FAKE_OUTPUT_DIR);
+
+      expect(resizeFn).toHaveBeenCalledWith({
+        width: 2048,
+        height: 2048,
+        fit: "inside",
+        withoutEnlargement: true,
+      });
+    });
+  });
+
+  describe("multiline and unicode text", () => {
+    it("handles multiline OCR text", async () => {
+      vi.mocked(parseStdoutJson).mockReturnValue({
+        success: true,
+        text: "Line 1\nLine 2\nLine 3",
+        engine: "paddleocr",
+      });
+
+      const result = await extractText(FAKE_INPUT, FAKE_OUTPUT_DIR);
+      expect(result.text).toBe("Line 1\nLine 2\nLine 3");
+    });
+
+    it("handles unicode text from CJK languages", async () => {
+      vi.mocked(parseStdoutJson).mockReturnValue({
+        success: true,
+        text: "你好世界",
+        engine: "paddleocr",
+      });
+
+      const result = await extractText(FAKE_INPUT, FAKE_OUTPUT_DIR);
+      expect(result.text).toBe("你好世界");
+    });
+  });
+
+  describe("sharp conversion errors", () => {
+    it("propagates sharp conversion errors", async () => {
+      vi.mocked(sharp).mockImplementation(
+        () =>
+          ({
+            resize: vi.fn().mockReturnThis(),
+            png: vi.fn().mockReturnThis(),
+            toBuffer: vi.fn().mockRejectedValue(new Error("Input buffer is empty")),
+            metadata: vi.fn().mockResolvedValue({ width: 800, height: 600 }),
+          }) as unknown as ReturnType<typeof sharp>,
+      );
+
+      await expect(extractText(FAKE_INPUT, FAKE_OUTPUT_DIR)).rejects.toThrow(
+        "Input buffer is empty",
+      );
+    });
   });
 });