test: update pre-existing stale specs for 2.0 multimodal + validation behavior

Fixes a backlog of integration/unit specs that asserted pre-2.0 behavior and
were failing CI (not caused by recent feature work):
- modality-aware empty-input error is 'No file(s) provided', not /no image/i
  (rotate, border, crop, resize, smart-crop, edge-cases, adversarial-extended,
  api, tool-factory-route)
- input validation rejects pre-enqueue with a clean 400 in 'error' (was a worker
  422 in 'details'): create-zip, extract-zip, merge-csvs
- resolveToolPool defaults unknown tools to the system pool (pool-routing)
- /upload and fetch-urls accept non-image content, validated per-tool at process
  time (api, fetch-urls)
- color-adjust legacy aliases were consolidated into adjust-colors: drop the
  removed-alias tests; retarget the format-preservation tests
- xml-to-csv gracefully converts a single non-repeating record to a 1-row CSV
- dropzone is multimodal; image-only filtering is opt-in via fileFilter
- factory-multi-input: register the synthetic test tools in the catalog so they
  route correctly (file modality for concat; image for the validation-prefix test)

Verified locally: unit 4546 passed, integration 8332 passed, typecheck + lint green.

tests/integration/fetch-urls.test.ts

@@ -136,7 +136,7 @@ describe("POST /api/v1/fetch-urls", () => {
     expect(body.results[0].error).toContain("404");
   });
 
-  it("returns failure for non-image content", async () => {
+  it("accepts non-image content (multimodal)", async () => {
     const res = await app.inject({
       method: "POST",
       url: "/api/v1/fetch-urls",
@@ -147,8 +147,8 @@ describe("POST /api/v1/fetch-urls", () => {
     expect(res.statusCode).toBe(200);
     const body = JSON.parse(res.body);
     expect(body.results).toHaveLength(1);
-    expect(body.results[0].success).toBe(false);
-    expect(body.results[0].error).toBeTruthy();
+    expect(body.results[0].success).toBe(true);
+    expect(body.results[0].downloadUrl).toBeDefined();
   });
 
   it("handles mixed batch with successes and failures", async () => {
@@ -173,7 +173,7 @@ describe("POST /api/v1/fetch-urls", () => {
     expect(body.results[0].filename).toBe("photo.jpg");
     expect(body.results[1].success).toBe(false);
     expect(body.results[1].error).toContain("404");
-    expect(body.results[2].success).toBe(false);
+    expect(body.results[2].success).toBe(true);
   });
 
   it("returns 400 for an empty URL array", async () => {