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/gui-tools-metadata.spec.ts

@@ -165,6 +165,23 @@ test.describe("GUI Metadata Tools", () => {
       await page.fill('[id="em-artist"]', "Modified Artist");
       await expect(page.getByText(/\d+ changes:/)).toBeVisible();
     });
+
+    test("shows copyright and description fields", async ({ loggedInPage: page }) => {
+      await page.goto("/edit-metadata");
+      await uploadTestImage(page);
+      await page.waitForSelector('[id="em-artist"]', { timeout: 10_000 });
+
+      await expect(page.locator("#em-copyright")).toBeVisible();
+      await expect(page.locator("#em-description")).toBeVisible();
+    });
+
+    test("submit button uses data-testid", async ({ loggedInPage: page }) => {
+      await page.goto("/edit-metadata");
+      await uploadTestImage(page);
+      await page.waitForSelector('[id="em-artist"]', { timeout: 10_000 });
+
+      await expect(page.getByTestId("edit-metadata-submit")).toBeVisible();
+    });
   });
 
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