fix(browser): harden extension relay worker recovery

Co-authored-by: codexGW <9350182+codexGW@users.noreply.github.com>

src/browser/chrome-extension-background-utils.test.ts

@@ -0,0 +1,77 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildRelayWsUrl,
+  isRetryableReconnectError,
+  reconnectDelayMs,
+} from "../../assets/chrome-extension/background-utils.js";
+
+describe("chrome extension background utils", () => {
+  it("builds websocket url with encoded gateway token", () => {
+    const url = buildRelayWsUrl(18792, "abc/+= token");
+    expect(url).toBe("ws://127.0.0.1:18792/extension?token=abc%2F%2B%3D%20token");
+  });
+
+  it("throws when gateway token is missing", () => {
+    expect(() => buildRelayWsUrl(18792, "")).toThrow(/Missing gatewayToken/);
+    expect(() => buildRelayWsUrl(18792, "   ")).toThrow(/Missing gatewayToken/);
+  });
+
+  it("uses exponential backoff from attempt index", () => {
+    expect(reconnectDelayMs(0, { baseMs: 1000, maxMs: 30000, jitterMs: 0, random: () => 0 })).toBe(
+      1000,
+    );
+    expect(reconnectDelayMs(1, { baseMs: 1000, maxMs: 30000, jitterMs: 0, random: () => 0 })).toBe(
+      2000,
+    );
+    expect(reconnectDelayMs(4, { baseMs: 1000, maxMs: 30000, jitterMs: 0, random: () => 0 })).toBe(
+      16000,
+    );
+  });
+
+  it("caps reconnect delay at max", () => {
+    const delay = reconnectDelayMs(20, {
+      baseMs: 1000,
+      maxMs: 30000,
+      jitterMs: 0,
+      random: () => 0,
+    });
+    expect(delay).toBe(30000);
+  });
+
+  it("adds jitter using injected random source", () => {
+    const delay = reconnectDelayMs(3, {
+      baseMs: 1000,
+      maxMs: 30000,
+      jitterMs: 1000,
+      random: () => 0.25,
+    });
+    expect(delay).toBe(8250);
+  });
+
+  it("sanitizes invalid attempts and options", () => {
+    expect(reconnectDelayMs(-2, { baseMs: 1000, maxMs: 30000, jitterMs: 0, random: () => 0 })).toBe(
+      1000,
+    );
+    expect(
+      reconnectDelayMs(Number.NaN, {
+        baseMs: Number.NaN,
+        maxMs: Number.NaN,
+        jitterMs: Number.NaN,
+        random: () => 0,
+      }),
+    ).toBe(1000);
+  });
+
+  it("marks missing token errors as non-retryable", () => {
+    expect(
+      isRetryableReconnectError(
+        new Error("Missing gatewayToken in extension settings (chrome.storage.local.gatewayToken)"),
+      ),
+    ).toBe(false);
+  });
+
+  it("keeps transient network errors retryable", () => {
+    expect(isRetryableReconnectError(new Error("WebSocket connect timeout"))).toBe(true);
+    expect(isRetryableReconnectError(new Error("Relay server not reachable"))).toBe(true);
+  });
+});

src/browser/chrome-extension-manifest.test.ts

@@ -0,0 +1,29 @@
+import { readFileSync } from "node:fs";
+import { resolve } from "node:path";
+import { describe, expect, it } from "vitest";
+
+type ExtensionManifest = {
+  background?: { service_worker?: string; type?: string };
+  permissions?: string[];
+};
+
+function readManifest(): ExtensionManifest {
+  const path = resolve(process.cwd(), "assets/chrome-extension/manifest.json");
+  return JSON.parse(readFileSync(path, "utf8")) as ExtensionManifest;
+}
+
+describe("chrome extension manifest", () => {
+  it("keeps background worker configured as module", () => {
+    const manifest = readManifest();
+    expect(manifest.background?.service_worker).toBe("background.js");
+    expect(manifest.background?.type).toBe("module");
+  });
+
+  it("includes resilience permissions", () => {
+    const permissions = readManifest().permissions ?? [];
+    expect(permissions).toContain("alarms");
+    expect(permissions).toContain("webNavigation");
+    expect(permissions).toContain("storage");
+    expect(permissions).toContain("debugger");
+  });
+});