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/integration/color-adjustments.test.ts

@@ -417,3 +417,123 @@ describe("Edge size inputs", () => {
     expect(result.processedSize).toBeGreaterThan(0);
   });
 });
+
+// ── Temperature + tint branch coverage ──────────────────────────
+describe("Temperature and tint isolation", () => {
+  it("applies only temperature (no tint)", async () => {
+    const res = await postTool("adjust-colors", { temperature: 80 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("applies only tint (no temperature)", async () => {
+    const res = await postTool("adjust-colors", { tint: 60 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("applies negative temperature (cool)", async () => {
+    const res = await postTool("adjust-colors", { temperature: -80 });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("applies negative tint", async () => {
+    const res = await postTool("adjust-colors", { tint: -80 });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("applies max temperature + max tint", async () => {
+    const res = await postTool("adjust-colors", { temperature: 100, tint: 100 });
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+// ── Saturation + hue isolation ──────────────────────────────────
+describe("Saturation and hue isolation", () => {
+  it("applies only saturation (no hue)", async () => {
+    const res = await postTool("adjust-colors", { saturation: -50 });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("applies only hue (no saturation)", async () => {
+    const res = await postTool("adjust-colors", { hue: 120 });
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+// ── Channel isolation ───────────────────────────────────────────
+describe("Channel isolation", () => {
+  it("adjusts only red channel", async () => {
+    const res = await postTool("adjust-colors", { red: 150 });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("adjusts only green channel", async () => {
+    const res = await postTool("adjust-colors", { green: 50 });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("adjusts only blue channel", async () => {
+    const res = await postTool("adjust-colors", { blue: 180 });
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+// ── Sharpness isolation ─────────────────────────────────────────
+describe("Sharpness isolation", () => {
+  it("applies max sharpness (100)", async () => {
+    const res = await postTool("adjust-colors", { sharpness: 100 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("applies zero sharpness (no-op)", async () => {
+    const res = await postTool("adjust-colors", { sharpness: 0 });
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+// ── Rejects invalid temperature/tint ────────────────────────────
+describe("Temperature/tint validation", () => {
+  it("rejects temperature out of range (>100)", async () => {
+    const res = await postTool("adjust-colors", { temperature: 150 });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("rejects tint out of range (>100)", async () => {
+    const res = await postTool("adjust-colors", { tint: 150 });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("rejects sharpness out of range (>100)", async () => {
+    const res = await postTool("adjust-colors", { sharpness: 150 });
+    expect(res.statusCode).toBe(400);
+  });
+});
+
+// ── Unauthenticated ─────────────────────────────────────────────
+describe("Authentication", () => {
+  it("rejects unauthenticated request", async () => {
+    const { body: payload, contentType } = makePayload({ brightness: 30 });
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/adjust-colors",
+      payload,
+      headers: { "content-type": contentType },
+    });
+    expect(res.statusCode).toBe(401);
+  });
+});
+
+// ── Effect: none (no-op effect) ─────────────────────────────────
+describe("No-op effect", () => {
+  it("applies 'none' effect (no color effect applied)", async () => {
+    const res = await postTool("adjust-colors", { effect: "none" });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+});