feat(search): add Xquik as an X search provider

Xquik needs a GET request with x-api-key auth and a tweets envelope
normalizer, neither of which the generic search fallback provides. Adds a
dedicated request builder and normalizer, cursor pagination passthrough,
result-based credit usage reporting, and a validateUrl probe so key
validation hits the no-charge credits endpoint.

open-sse/handlers/search/callers.js

@@ -347,6 +347,33 @@ function buildSearxngRequest(config, params) {
   };
 }
 
+function buildXquikRequest(config, params) {
+  const apiKey = params.token;
+  if (!apiKey) throw new Error("Xquik requires an API key");
+
+  const queryType = getProviderSetting(params, "queryType");
+  if (queryType && !["Latest", "Top"].includes(queryType)) {
+    throw new Error("Xquik queryType must be Latest or Top");
+  }
+
+  const qp = new URLSearchParams({
+    q: params.query,
+    limit: String(params.maxResults),
+  });
+  const cursor = getProviderSetting(params, "cursor");
+  if (cursor) qp.set("cursor", cursor);
+  if (queryType) qp.set("queryType", queryType);
+  if (params.language) qp.set("language", params.language);
+
+  return {
+    url: `${resolveBaseUrl(config, params)}?${qp}`,
+    init: {
+      method: "GET",
+      headers: { Accept: "application/json", "x-api-key": apiKey },
+    },
+  };
+}
+
 // ── Dispatcher ──────────────────────────────────────────────────────────
 
 const BUILDERS = {
@@ -360,6 +387,7 @@ const BUILDERS = {
   "searchapi": buildSearchApiRequest,
   "youcom": buildYouComRequest,
   "searxng": buildSearxngRequest,
+  "xquik": buildXquikRequest,
 };
 
 /**