test: comprehensive test coverage expansion (+965 tests)

Add 42 new test files covering all untested tool routes, image engine
internals, AI sidecar bridge, Zustand stores, and cross-format
compatibility. Expand e2e-docker suite with 7 spec files covering all
48 tools against a real Docker container.

Unit tests:
- Image engine: format detection, MIME mapping, metadata parsing, pipeline
- AI bridge: sidecar lifecycle, all 11 tool functions (mocked)
- Web stores: 14 Zustand stores (collage, settings, features, analytics, etc.)
- API helpers: format decoders, page range, file validation

Integration tests:
- 25 tool routes that had zero dedicated tests
- Cross-format matrix: 17 input formats x 3 tools
- Edge cases: zero-byte files, corrupted headers, path traversal, XSS, SQL injection
- Concurrent request handling and pipeline edge cases

E2E-Docker (Playwright against real container):
- 7 spec files: essential, adjustment, conversion, creative, utility, AI, pipeline
- Custom buildMultipart helper for multi-file tool uploads
- AI tools gracefully skip when sidecar not installed

Fixtures:
- Organized test media: formats/ (18 formats) + content/ (17 content types)
- Reduced from 3.1 GB unorganized samples to 33 MB structured fixtures

Bug fix:
- color-adjustments: gamma exposure used invalid single-param gamma() for
  positive values; fixed to use two-param gamma(gammaIn, gammaOut) form

tests/integration/sharpening.test.ts

@@ -0,0 +1,246 @@
+/**
+ * Integration tests for the sharpening tool.
+ *
+ * Tests all three sharpening methods (adaptive, unsharp-mask, high-pass),
+ * custom parameters, denoise option, and format support.
+ */
+
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import sharp from "sharp";
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { buildTestApp, createMultipartPayload, loginAsAdmin, type TestApp } from "./test-server.js";
+
+const FIXTURES = join(__dirname, "..", "fixtures");
+const PNG = readFileSync(join(FIXTURES, "test-200x150.png"));
+const JPG = readFileSync(join(FIXTURES, "test-100x100.jpg"));
+const WEBP = readFileSync(join(FIXTURES, "test-50x50.webp"));
+
+let testApp: TestApp;
+let app: TestApp["app"];
+let adminToken: string;
+
+beforeAll(async () => {
+  testApp = await buildTestApp();
+  app = testApp.app;
+  adminToken = await loginAsAdmin(app);
+}, 30_000);
+
+afterAll(async () => {
+  await testApp.cleanup();
+}, 10_000);
+
+function makePayload(
+  settings: Record<string, unknown>,
+  buffer: Buffer = PNG,
+  filename = "test.png",
+  contentType = "image/png",
+) {
+  return createMultipartPayload([
+    { name: "file", filename, contentType, content: buffer },
+    { name: "settings", content: JSON.stringify(settings) },
+  ]);
+}
+
+async function postTool(
+  settings: Record<string, unknown>,
+  buffer?: Buffer,
+  filename?: string,
+  ct?: string,
+) {
+  const { body: payload, contentType } = makePayload(settings, buffer, filename, ct);
+  return app.inject({
+    method: "POST",
+    url: "/api/v1/tools/sharpening",
+    payload,
+    headers: {
+      "content-type": contentType,
+      authorization: `Bearer ${adminToken}`,
+    },
+  });
+}
+
+// ── Adaptive method (default) ─────────────────────────────────────
+describe("Adaptive sharpening", () => {
+  it("sharpens with default settings", async () => {
+    const res = await postTool({});
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+
+  it("sharpens with custom sigma", async () => {
+    const res = await postTool({ method: "adaptive", sigma: 3.0 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("sharpens with all adaptive parameters", async () => {
+    const res = await postTool({
+      method: "adaptive",
+      sigma: 2.0,
+      m1: 2.0,
+      m2: 5.0,
+      x1: 3.0,
+      y2: 15,
+      y3: 25,
+    });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+});
+
+// ── Unsharp mask method ───────────────────────────────────────────
+describe("Unsharp mask sharpening", () => {
+  it("sharpens with unsharp-mask method", async () => {
+    const res = await postTool({ method: "unsharp-mask" });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("sharpens with custom amount and radius", async () => {
+    const res = await postTool({
+      method: "unsharp-mask",
+      amount: 200,
+      radius: 2.5,
+      threshold: 10,
+    });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+});
+
+// ── High-pass method ──────────────────────────────────────────────
+describe("High-pass sharpening", () => {
+  it("sharpens with high-pass method", async () => {
+    const res = await postTool({ method: "high-pass" });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("sharpens with custom strength and kernel size 5", async () => {
+    const res = await postTool({ method: "high-pass", strength: 80, kernelSize: 5 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+});
+
+// ── Denoise option ────────────────────────────────────────────────
+describe("Denoise option", () => {
+  it("applies light denoise", async () => {
+    const res = await postTool({ denoise: "light" });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("applies medium denoise", async () => {
+    const res = await postTool({ denoise: "medium" });
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("applies strong denoise", async () => {
+    const res = await postTool({ denoise: "strong" });
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+// ── Output verification ──────────────────────────────────────────
+describe("Output verification", () => {
+  it("output differs from input (sharpening changes data)", async () => {
+    const res = await postTool({ method: "adaptive", sigma: 5.0 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+
+    const dlRes = await app.inject({
+      method: "GET",
+      url: result.downloadUrl,
+      headers: { authorization: `Bearer ${adminToken}` },
+    });
+    expect(dlRes.statusCode).toBe(200);
+
+    // Sharpened output should not be identical to input
+    expect(Buffer.compare(dlRes.rawPayload, PNG)).not.toBe(0);
+  });
+
+  it("preserves image dimensions", async () => {
+    const res = await postTool({ method: "unsharp-mask", amount: 300 });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+
+    const dlRes = await app.inject({
+      method: "GET",
+      url: result.downloadUrl,
+      headers: { authorization: `Bearer ${adminToken}` },
+    });
+    const meta = await sharp(dlRes.rawPayload).metadata();
+    expect(meta.width).toBe(200);
+    expect(meta.height).toBe(150);
+  });
+});
+
+// ── Format support ────────────────────────────────────────────────
+describe("Multiple input formats", () => {
+  it("processes JPEG input", async () => {
+    const res = await postTool({ method: "adaptive" }, JPG, "test.jpg", "image/jpeg");
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("processes WebP input", async () => {
+    const res = await postTool({ method: "adaptive" }, WEBP, "test.webp", "image/webp");
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+});
+
+// ── Error handling ────────────────────────────────────────────────
+describe("Error handling", () => {
+  it("returns 400 when no file is provided", async () => {
+    const { body: payload, contentType } = createMultipartPayload([
+      { name: "settings", content: JSON.stringify({ method: "adaptive" }) },
+    ]);
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/sharpening",
+      payload,
+      headers: {
+        "content-type": contentType,
+        authorization: `Bearer ${adminToken}`,
+      },
+    });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for invalid method", async () => {
+    const res = await postTool({ method: "gaussian" });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for sigma out of range (too low)", async () => {
+    const res = await postTool({ sigma: 0.1 });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for sigma out of range (too high)", async () => {
+    const res = await postTool({ sigma: 50 });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for invalid kernelSize", async () => {
+    const res = await postTool({ method: "high-pass", kernelSize: 7 });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for invalid denoise value", async () => {
+    const res = await postTool({ denoise: "extreme" });
+    expect(res.statusCode).toBe(400);
+  });
+});