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-keyboard.spec.ts

@@ -1,4 +1,4 @@
-import { expect, test } from "./helpers";
+import { expect, openSettings, test } from "./helpers";
 
 // ---------------------------------------------------------------------------
 // Helper: the correct modifier key for the OS running Playwright
@@ -197,3 +197,108 @@ test.describe("Keyboard Shortcuts - Input Suppression", () => {
     await expect(page).toHaveURL("/fullscreen");
   });
 });
+
+// ---------------------------------------------------------------------------
+// Escape key behavior
+// ---------------------------------------------------------------------------
+test.describe("Keyboard Shortcuts - Escape Key", () => {
+  test("Escape closes the settings dialog", async ({ loggedInPage: page }) => {
+    await openSettings(page);
+
+    await expect(page.getByRole("dialog")).toBeVisible();
+
+    await page.keyboard.press("Escape");
+    await page.waitForTimeout(300);
+
+    await expect(page.getByRole("dialog")).not.toBeVisible();
+  });
+
+  test("Escape closes the help dialog", async ({ loggedInPage: page }) => {
+    await page.locator("aside").getByText("Help").click();
+
+    await expect(page.getByRole("heading", { name: "Help" })).toBeVisible();
+
+    await page.keyboard.press("Escape");
+    await page.waitForTimeout(300);
+
+    await expect(page.getByRole("heading", { name: "Help" })).not.toBeVisible();
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Shortcut suppression in textarea and contenteditable
+// ---------------------------------------------------------------------------
+test.describe("Keyboard Shortcuts - Textarea Suppression", () => {
+  test("Cmd/Ctrl+/ does not navigate when focused on textarea", async ({ loggedInPage: page }) => {
+    // Navigate to a tool that has a textarea (watermark-text has text input)
+    await page.goto("/watermark-text");
+
+    // Find a textarea or contenteditable element on the page
+    const textarea = page.locator("textarea").first();
+    if (await textarea.isVisible({ timeout: 3000 }).catch(() => false)) {
+      await textarea.click();
+
+      await page.keyboard.press(`${MOD}+/`);
+      await page.waitForTimeout(300);
+
+      // Should still be on watermark-text since shortcut was suppressed in textarea
+      await expect(page).toHaveURL("/watermark-text");
+    }
+  });
+
+  test("Cmd/Ctrl+Shift+D does not toggle theme when focused on a textarea", async ({
+    loggedInPage: page,
+  }) => {
+    await page.goto("/watermark-text");
+
+    const textarea = page.locator("textarea").first();
+    if (await textarea.isVisible({ timeout: 3000 }).catch(() => false)) {
+      await textarea.click();
+
+      const hadDark = await page.evaluate(() =>
+        document.documentElement.classList.contains("dark"),
+      );
+
+      await page.keyboard.press(`${MOD}+Shift+d`);
+      await page.waitForTimeout(300);
+
+      const hasDark = await page.evaluate(() =>
+        document.documentElement.classList.contains("dark"),
+      );
+
+      // Theme should NOT have changed since we were in a textarea
+      expect(hasDark).toBe(hadDark);
+    }
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Keyboard accessibility - focus management
+// ---------------------------------------------------------------------------
+test.describe("Keyboard Accessibility", () => {
+  test("Tab key cycles through interactive elements on home page", async ({
+    loggedInPage: page,
+  }) => {
+    // Press Tab several times and verify focus moves to interactive elements
+    await page.keyboard.press("Tab");
+    await page.waitForTimeout(100);
+
+    // After tabbing, some element should be focused
+    const focusedTag = await page.evaluate(() => document.activeElement?.tagName?.toLowerCase());
+    expect(["a", "button", "input", "select", "textarea"]).toContain(focusedTag);
+  });
+
+  test("search input is reachable via keyboard", async ({ loggedInPage: page }) => {
+    // Cmd+K should focus the search bar without needing to Tab to it
+    await page.keyboard.press(`${MOD}+k`);
+
+    const searchInput = page.getByPlaceholder(/search/i).first();
+    await expect(searchInput).toBeFocused();
+
+    // Typing should filter tools
+    await page.keyboard.type("resize");
+    await page.waitForTimeout(300);
+
+    await expect(page.getByText("Resize").first()).toBeVisible();
+  });
+});