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/create-zip.test.ts

@@ -47,7 +47,7 @@ describe("create-zip (pure JS, no skipIf)", () => {
     expect(dl.rawPayload.length).toBeGreaterThan(CSV_A.length + CSV_B.length - 50);
   }, 30_000);
 
-  it("rejects a single file with 422 'at least two'", async () => {
+  it("rejects a single file with 400 'at least two'", async () => {
     const { body, contentType } = createMultipartPayload([
       { name: "file", filename: "tiny-a.csv", contentType: "text/csv", content: CSV_A },
       { name: "settings", content: JSON.stringify({}) },
@@ -59,8 +59,8 @@ describe("create-zip (pure JS, no skipIf)", () => {
       body,
     });
 
-    expect(res.statusCode).toBe(422);
+    expect(res.statusCode).toBe(400);
     const parsed = JSON.parse(res.body);
-    expect(parsed.details).toMatch(/at least two/i);
+    expect(parsed.error).toMatch(/at least 2/i);
   }, 30_000);
 });