fix: resolve pre-existing test failures for content-aware-crop removal and watermark validation

- Replace content-aware-crop with ai-canvas-expand in TOOLS[], AI_TOOL_IDS,
  and FEATURE_BUNDLES (matching the already-updated tool-registry.tsx and
  feature-manifest.json from commit c6a5d3f)
- Fix trailing syntax error in features.ts (extra closing brace)
- Add ai-canvas-expand-settings mock to tool-registry test files
- Update watermark-image tests to expect 400 (validation rejection) instead
  of 422 (processing failure) for corrupted image buffers, matching the
  actual route behavior where validateImageBuffer catches them first

tests/integration/watermark-image.test.ts

@@ -210,8 +210,8 @@ describe("watermark-image", () => {
 
   // ── Branch coverage: lines 164-168 (processing failure) ───────────
 
-  it("returns 422 when processing fails on corrupted main image", async () => {
-    // A buffer that passes multipart parsing but fails Sharp processing
+  it("returns 400 when main image is corrupted", async () => {
+    // A buffer that passes multipart parsing but fails image validation
     const corruptedBuffer = Buffer.alloc(100, 0xff);
     const { body, contentType } = createMultipartPayload([
       { name: "file", filename: "main.png", contentType: "image/png", content: corruptedBuffer },
@@ -226,9 +226,9 @@ describe("watermark-image", () => {
       body,
     });
 
-    expect(res.statusCode).toBe(422);
+    expect(res.statusCode).toBe(400);
     const json = JSON.parse(res.body);
-    expect(json.error).toContain("Processing failed");
+    expect(json.error).toContain("Invalid image");
   });
 
   // ── HEIC input handling ───────────────────────────────────────────
@@ -338,7 +338,7 @@ describe("watermark-image", () => {
 
   // ── Corrupted watermark image (processing failure) ───────────────
 
-  it("returns 422 when watermark image is corrupted", async () => {
+  it("returns 400 when watermark image is corrupted", async () => {
     const corruptedWm = Buffer.alloc(50, 0xaa);
     const { body, contentType } = createMultipartPayload([
       { name: "file", filename: "main.png", contentType: "image/png", content: PNG },
@@ -353,9 +353,9 @@ describe("watermark-image", () => {
       body,
     });
 
-    expect(res.statusCode).toBe(422);
+    expect(res.statusCode).toBe(400);
     const json = JSON.parse(res.body);
-    expect(json.error).toContain("Processing failed");
+    expect(json.error).toContain("Invalid watermark image");
   });
 
   // ── Tiny 1x1 main image ──────────────────────────────────────────

tests/unit/web/tool-registry-expanded.test.ts

@@ -138,6 +138,9 @@ vi.mock("@/components/tools/meme-generator-preview", () => ({
 vi.mock("@/components/tools/color-blindness-settings", () => ({
   ColorBlindnessSettings: () => null,
 }));
+vi.mock("@/components/tools/ai-canvas-expand-settings", () => ({
+  AiCanvasExpandSettings: () => null,
+}));
 
 import { TOOLS } from "@snapotter/shared";
 import type { DisplayMode, ToolRegistryEntry } from "@/lib/tool-registry";

tests/unit/web/tool-registry.test.ts

@@ -181,6 +181,9 @@ vi.mock("@/components/tools/meme-generator-preview", () => ({
 vi.mock("@/components/tools/color-blindness-settings", () => ({
   ColorBlindnessSettings: () => null,
 }));
+vi.mock("@/components/tools/ai-canvas-expand-settings", () => ({
+  AiCanvasExpandSettings: () => null,
+}));
 
 // ---------------------------------------------------------------------------
 // Import after mocks