fix(ai-contracts): customNodeFetch för att kringgå IPv6-häng i WSL

Node.js fetch() hänger på POST till Gemini via IPv6 i WSL.
Ersätter default fetch med customNodeFetch som använder node:https
och därmed kör över IPv4. Signifikant hastighetsförbättring
(~1 sek vs timeout).

Relaterat till scale-batch.ts i Fas A Steg 2.

packages/ai-contracts/src/gemini.ts

@@ -23,6 +23,61 @@ import type { LocaleContext } from "@app/shared-types";
 
 const GEMINI_API_BASE = "https://generativelanguage.googleapis.com/v1beta";
 
+/** Custom fetch using Node https module — works around IPv6 hangs on WSL. */
+function customNodeFetch(input: string | URL | Request, init?: RequestInit): Promise<Response> {
+  return new Promise((resolve, reject) => {
+    const url = typeof input === "string" ? input : input instanceof URL ? input.toString() : input.url;
+    const u = new URL(url);
+    const isHttps = u.protocol === "https:";
+    const mod = isHttps ? import("node:https") : import("node:http");
+    mod.then((httpMod) => {
+      const postData = init?.body ? String(init.body) : undefined;
+      const headers: Record<string, string> = {};
+      if (init?.headers) {
+        if (init.headers instanceof Headers) {
+          init.headers.forEach((v, k) => { headers[k] = v; });
+        } else if (Array.isArray(init.headers)) {
+          (init.headers as [string, string][]).forEach(([k, v]) => { if (k != null) headers[k] = v; });
+        } else {
+          Object.assign(headers, init.headers as Record<string, string>);
+        }
+      }
+      if (postData && !headers["content-length"]) {
+        headers["content-length"] = String(Buffer.byteLength(postData));
+      }
+
+      const req = httpMod.request(
+        {
+          hostname: u.hostname,
+          port: u.port || (isHttps ? 443 : 80),
+          path: u.pathname + u.search,
+          method: init?.method || "GET",
+          headers,
+          timeout: 120_000,
+        },
+        (res) => {
+          let body = "";
+          res.setEncoding("utf8");
+          res.on("data", (chunk) => { body += chunk; });
+          res.on("end", () => {
+            resolve(
+              new Response(body, {
+                status: res.statusCode ?? 200,
+                statusText: res.statusMessage ?? "OK",
+                headers: new Headers(Object.entries(res.headers).map(([k, v]) => [k, String(v)])),
+              }),
+            );
+          });
+        },
+      );
+      req.on("error", (err) => reject(err));
+      req.on("timeout", () => { req.destroy(); reject(new Error("Request timeout")); });
+      if (postData) req.write(postData);
+      req.end();
+    }).catch(reject);
+  });
+}
+
 /** Estimated max cost per image call in USD (pessimistic). */
 const COST_ESTIMATE_PER_IMAGE_USD = 0.0015;
 
@@ -160,7 +215,7 @@ export class GeminiAamosClient implements AamosClient {
       timeoutMs: config.timeoutMs ?? 60_000,
       dailyBudgetUsd: config.dailyBudgetUsd ?? 0,
       promptVersion: config.promptVersion ?? "gemini-fridge-v1",
-      fetchImpl: config.fetchImpl ?? fetch,
+      fetchImpl: config.fetchImpl ?? customNodeFetch,
       budgetStore: config.budgetStore,
     };
   }