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/xml-to-csv.test.ts

@@ -48,11 +48,22 @@ describe("xml-to-csv (pure JS, no skipIf)", () => {
     expect(text).toContain("Grace");
   }, 30_000);
 
-  it("rejects XML with no repeating elements", async () => {
+  it("converts single non-repeating record to a 1-row CSV", async () => {
     const xml = Buffer.from('<?xml version="1.0"?><root><single>value</single></root>');
     const res = await runTool("flat.xml", xml);
-    expect(res.statusCode).toBe(422);
-    const parsed = JSON.parse(res.body);
-    expect(parsed.details).toMatch(/no repeating elements/i);
+    expect(res.statusCode).toBe(200);
+    const envelope = JSON.parse(res.body);
+    expect(envelope.downloadUrl).toBeDefined();
+    expect(envelope.rows).toBe(1);
+
+    const dl = await testApp.app.inject({ method: "GET", url: envelope.downloadUrl });
+    expect(dl.statusCode).toBe(200);
+
+    const text = dl.payload;
+    const lines = text.trim().split("\n");
+    // header + 1 data row
+    expect(lines.length).toBe(2);
+    expect(text).toContain("single");
+    expect(text).toContain("value");
   }, 30_000);
 });