test: major coverage expansion — 18 new test files, ~830 new tests

Unit tests: 1354 → 1781 (+427)
- 11 new AI bridge module tests (packages/ai/ from 2/13 → 13/13 files)
- files-page-store (0% → full), pdf-to-image-store, features-store expanded
- saturation and edit-metadata image-engine operations
- analytics route, features route, web analytics lib, api-extended

Integration tests: ~2070 → 2320 (+250)
- 31 integration files expanded with branch-coverage-targeted tests
- progress.ts SSE endpoints (28% → comprehensive, +18 tests)
- gif-tools all modes (+18), pdf-to-image format variants (+13)
- Cross-format matrix expanded to 17 tools × 17 formats (467 tests)
- Adversarial: concurrent, memory pressure, unicode filenames, pipeline limits

E2E-Docker: +1020 lines across 6 spec files
- Info, colors, sharpening, base64, QR read, JXL/ICO/SVG formats
- Strip-metadata, image-enhancement, content-aware-resize expanded
- Batch pipelines, multi-format batches, HEIC input coverage

tests/integration/watermark-text.test.ts

@@ -7,6 +7,7 @@
 
 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";
 
@@ -200,4 +201,150 @@ describe("watermark-text", () => {
 
     expect(res.statusCode).toBe(400);
   });
+
+  // ── Branch coverage: lines 45-46 (metadata fallback for width/height) ──
+
+  it("handles tiny 1x1 image input", async () => {
+    const TINY = readFileSync(join(FIXTURES, "test-1x1.png"));
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tiny.png", contentType: "image/png", content: TINY },
+      { name: "settings", content: JSON.stringify({ text: "Tiny", position: "center" }) },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const json = JSON.parse(res.body);
+    expect(json.downloadUrl).toBeDefined();
+  });
+
+  // ── Branch coverage: line 61 (tiled with maxElements cap) ─────────
+
+  it("handles tiled watermark on a large image", async () => {
+    const LARGE = readFileSync(join(FIXTURES, "content", "stress-large.jpg"));
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "large.jpg", contentType: "image/jpeg", content: LARGE },
+      {
+        name: "settings",
+        content: JSON.stringify({
+          text: "CONFIDENTIAL",
+          position: "tiled",
+          fontSize: 12,
+          rotation: -30,
+        }),
+      },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const json = JSON.parse(res.body);
+    expect(json.processedSize).toBeGreaterThan(0);
+  });
+
+  // ── HEIC input handling ───────────────────────────────────────────
+
+  it("handles HEIC input", async () => {
+    const HEIC = readFileSync(join(FIXTURES, "test-200x150.heic"));
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "photo.heic", contentType: "image/heic", content: HEIC },
+      { name: "settings", content: JSON.stringify({ text: "HEIC Test" }) },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const json = JSON.parse(res.body);
+    expect(json.downloadUrl).toBeDefined();
+  });
+
+  // ── XML escaping in text ──────────────────────────────────────────
+
+  it("handles special XML characters in watermark text", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "test.png", contentType: "image/png", content: PNG },
+      {
+        name: "settings",
+        content: JSON.stringify({ text: '<Test & "Quotes">' }),
+      },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const json = JSON.parse(res.body);
+    expect(json.downloadUrl).toBeDefined();
+  });
+
+  // ── Tiled with small fontSize produces many elements ──────────────
+
+  it("handles tiled watermark with very small fontSize", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "test.png", contentType: "image/png", content: PNG },
+      {
+        name: "settings",
+        content: JSON.stringify({
+          text: "W",
+          position: "tiled",
+          fontSize: 8,
+        }),
+      },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+  });
+
+  // ── JPEG format preserves as JPEG ─────────────────────────────────
+
+  it("preserves JPEG format", async () => {
+    const JPG = readFileSync(join(FIXTURES, "test-100x100.jpg"));
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "test.jpg", contentType: "image/jpeg", content: JPG },
+      { name: "settings", content: JSON.stringify({ text: "JPEG" }) },
+    ]);
+
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/watermark-text",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const json = JSON.parse(res.body);
+    const dlRes = await app.inject({
+      method: "GET",
+      url: json.downloadUrl,
+      headers: { authorization: `Bearer ${adminToken}` },
+    });
+    const meta = await sharp(dlRes.rawPayload).metadata();
+    expect(meta.format).toBe("jpeg");
+  });
 });