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/e2e/gui-keyboard.spec.ts

@@ -0,0 +1,134 @@
+import { expect, test } from "./helpers";
+
+// ---------------------------------------------------------------------------
+// Helper: the correct modifier key for the OS running Playwright
+// On macOS Playwright uses "Meta", on others "Control".
+// ---------------------------------------------------------------------------
+const MOD = process.platform === "darwin" ? "Meta" : "Control";
+
+// ---------------------------------------------------------------------------
+// Keyboard Shortcuts
+// ---------------------------------------------------------------------------
+test.describe("Keyboard Shortcuts", () => {
+  test("Cmd/Ctrl+K focuses the search bar", async ({ loggedInPage: page }) => {
+    // Ensure search bar exists but is not focused
+    const searchInput = page.getByPlaceholder(/search/i).first();
+    await expect(searchInput).toBeVisible();
+
+    await page.keyboard.press(`${MOD}+k`);
+
+    await expect(searchInput).toBeFocused();
+  });
+
+  test("Cmd/Ctrl+/ navigates to tools (home) page", async ({ loggedInPage: page }) => {
+    await page.goto("/automate");
+    await expect(page).toHaveURL("/automate");
+
+    await page.keyboard.press(`${MOD}+/`);
+
+    await expect(page).toHaveURL("/");
+  });
+
+  test("Cmd/Ctrl+Shift+D toggles the theme", async ({ loggedInPage: page }) => {
+    // Check the initial dark class state
+    const hadDarkBefore = await page.evaluate(() =>
+      document.documentElement.classList.contains("dark"),
+    );
+
+    await page.keyboard.press(`${MOD}+Shift+d`);
+
+    // Wait briefly for the class toggle to apply
+    await page.waitForTimeout(300);
+
+    const hasDarkAfter = await page.evaluate(() =>
+      document.documentElement.classList.contains("dark"),
+    );
+
+    // Theme should have toggled
+    expect(hasDarkAfter).not.toBe(hadDarkBefore);
+  });
+
+  test("Cmd/Ctrl+Shift+D toggles theme back on second press", async ({ loggedInPage: page }) => {
+    const initial = await page.evaluate(() => document.documentElement.classList.contains("dark"));
+
+    // First toggle
+    await page.keyboard.press(`${MOD}+Shift+d`);
+    await page.waitForTimeout(300);
+
+    // Second toggle
+    await page.keyboard.press(`${MOD}+Shift+d`);
+    await page.waitForTimeout(300);
+
+    const afterDouble = await page.evaluate(() =>
+      document.documentElement.classList.contains("dark"),
+    );
+
+    expect(afterDouble).toBe(initial);
+  });
+
+  test("shortcuts do not fire when typing in an input field", async ({ loggedInPage: page }) => {
+    // Focus the search input
+    const searchInput = page.getByPlaceholder(/search/i).first();
+    await searchInput.click();
+    await searchInput.fill("");
+
+    // Press Cmd+/ which normally navigates to /
+    // But since we're in an input, it should NOT navigate
+    await page.goto("/fullscreen");
+    await page.waitForTimeout(300);
+
+    const searchOnFullscreen = page.getByPlaceholder(/search/i);
+    await searchOnFullscreen.click();
+
+    // Type the / character while focused on input - this should not navigate
+    await page.keyboard.press(`${MOD}+/`);
+    await page.waitForTimeout(300);
+
+    // Should still be on fullscreen since the shortcut was suppressed
+    await expect(page).toHaveURL("/fullscreen");
+  });
+
+  test("Cmd/Ctrl+K works even when focused on an input field", async ({ loggedInPage: page }) => {
+    // Navigate to fullscreen which has its own search input
+    await page.goto("/fullscreen");
+
+    const searchInput = page.getByPlaceholder(/search/i);
+    await searchInput.click();
+    await searchInput.fill("test");
+
+    // Cmd+K is the exception - it should still fire in inputs
+    await page.keyboard.press(`${MOD}+k`);
+
+    // The search input should be focused and selected
+    await expect(searchInput).toBeFocused();
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Tool navigation shortcuts (Cmd+Alt+N)
+// ---------------------------------------------------------------------------
+test.describe("Keyboard Shortcuts - Tool Navigation", () => {
+  test("Cmd/Ctrl+Alt+1 navigates to Resize", async ({ loggedInPage: page }) => {
+    await page.keyboard.press(`${MOD}+Alt+1`);
+
+    await expect(page).toHaveURL("/resize");
+  });
+
+  test("Cmd/Ctrl+Alt+2 navigates to Crop", async ({ loggedInPage: page }) => {
+    await page.keyboard.press(`${MOD}+Alt+2`);
+
+    await expect(page).toHaveURL("/crop");
+  });
+
+  test("Cmd/Ctrl+Alt+3 navigates to Compress", async ({ loggedInPage: page }) => {
+    await page.keyboard.press(`${MOD}+Alt+3`);
+
+    await expect(page).toHaveURL("/compress");
+  });
+
+  test("Cmd/Ctrl+Alt+4 navigates to Convert", async ({ loggedInPage: page }) => {
+    await page.keyboard.press(`${MOD}+Alt+4`);
+
+    await expect(page).toHaveURL("/convert");
+  });
+});