test: update tests and comments to reflect new autoSelectFamily default

- Update test expectation: 'defaults to enable on Node 22'
- Update comment in fetch.ts to explain IPv4 fallback rationale
- Addresses greptile review feedback

src/telegram/fetch.ts

@@ -7,7 +7,8 @@ import { resolveTelegramAutoSelectFamilyDecision } from "./network-config.js";
 let appliedAutoSelectFamily: boolean | null = null;
 const log = createSubsystemLogger("telegram/network");
 
-// Node 22 workaround: disable autoSelectFamily to avoid Happy Eyeballs timeouts.
+// Node 22 workaround: enable autoSelectFamily to allow IPv4 fallback on broken IPv6 networks.
+// Many networks have IPv6 configured but not routed, causing "Network is unreachable" errors.
 // See: https://github.com/nodejs/node/issues/54359
 function applyTelegramNetworkWorkarounds(network?: TelegramNetworkConfig): void {
   const decision = resolveTelegramAutoSelectFamilyDecision({ network });

src/telegram/network-config.test.ts

@@ -36,9 +36,9 @@ describe("resolveTelegramAutoSelectFamilyDecision", () => {
     expect(decision).toEqual({ value: true, source: "config" });
   });
 
-  it("defaults to disable on Node 22", () => {
+  it("defaults to enable on Node 22", () => {
     const decision = resolveTelegramAutoSelectFamilyDecision({ env: {}, nodeMajor: 22 });
-    expect(decision).toEqual({ value: false, source: "default-node22" });
+    expect(decision).toEqual({ value: true, source: "default-node22" });
   });
 
   it("returns null when no decision applies", () => {