test: massive test coverage expansion (+1,437 tests, 22 new files)

Expand test coverage across all layers via 14 parallel agents:

Unit tests (3,378 total, +534):
- First-ever AI sidecar tests (157 tests covering bridge lifecycle, all 12 tool modules)
- API route infrastructure (auth, pipeline, batch, settings, teams, roles, audit, api-keys, files, docs)
- Lib coverage improvements (audit 7%->95%, worker-pool 33%->100%)
- Web store/lib gap fills (features-store, tool-registry)

Integration tests (4,403 total, +903):
- Expanded 19 tool test files with parameter variations, format edge cases, boundary values
- Cross-format matrix: 290 tests covering 14 tools x 17 formats
- Adversarial/edge cases: 63 tests for extreme inputs, concurrent requests, corrupted files

E2E-Docker (125 new tests):
- Expanded 8 spec files + 1 new file covering all 49 tools
- Added HEIC/format handling, auth failures, download verification

GUI E2E (expanded 28 spec files):
- Navigation, responsive layout, keyboard shortcuts
- All 51 tool UIs with settings, processing, display modes
- Batch/pipeline workflows, settings/RBAC, visual regression
- Resilience, accessibility (ARIA, contrast, focus), performance budgets

tests/e2e-landing/accessibility.spec.ts

@@ -54,19 +54,13 @@ test.describe("Meta Tags", () => {
     const metaDesc = page.locator('meta[name="description"]');
     const content = await metaDesc.getAttribute("content");
     expect(content).toBeTruthy();
-    expect(content!.length).toBeGreaterThan(10);
+    expect(content?.length).toBeGreaterThan(10);
   });
 
   test("homepage has Open Graph tags", async ({ page }) => {
     await page.goto("/");
-    await expect(page.locator('meta[property="og:title"]')).toHaveAttribute(
-      "content",
-      /.+/,
-    );
-    await expect(page.locator('meta[property="og:description"]')).toHaveAttribute(
-      "content",
-      /.+/,
-    );
+    await expect(page.locator('meta[property="og:title"]')).toHaveAttribute("content", /.+/);
+    await expect(page.locator('meta[property="og:description"]')).toHaveAttribute("content", /.+/);
   });
 });