Analytics configuration is the responsibility of the host application when running in widget mode (#3089)

* Support for analytics configuration via URL parameters in widget mode

Adds:

- posthogApiHost
- posthogApiKey
- rageshakeSubmitUrl
- sentryDsn
- sentryEnvironment

Deprecate analyticsId and use posthogUserId instead

* Partial test coverage

* Simplify tests

* More tests

* Lint

* Split embedded only parameters into own section for clarity

* Update docs/url-params.md

* Update docs/url-params.md

* Update vite.config.js

src/analytics/PosthogAnalytics.test.ts

@@ -0,0 +1,91 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  expect,
+  describe,
+  it,
+  vi,
+  beforeEach,
+  beforeAll,
+  afterAll,
+} from "vitest";
+
+import { PosthogAnalytics } from "./PosthogAnalytics";
+import { mockConfig } from "../utils/test";
+
+describe("PosthogAnalytics", () => {
+  describe("embedded package", () => {
+    beforeAll(() => {
+      vi.stubEnv("VITE_PACKAGE", "embedded");
+    });
+
+    beforeEach(() => {
+      mockConfig({});
+      window.location.hash = "#";
+      PosthogAnalytics.resetInstance();
+    });
+
+    afterAll(() => {
+      vi.unstubAllEnvs();
+    });
+
+    it("does not create instance without config value or URL params", () => {
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(false);
+    });
+
+    it("ignores config value and does not create instance", () => {
+      mockConfig({
+        posthog: {
+          api_host: "https://api.example.com.localhost",
+          api_key: "api_key",
+        },
+      });
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(false);
+    });
+
+    it("uses URL params if both set", () => {
+      window.location.hash = `#?posthogApiHost=${encodeURIComponent("https://url.example.com.localhost")}&posthogApiKey=api_key`;
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(true);
+    });
+  });
+
+  describe("full package", () => {
+    beforeAll(() => {
+      vi.stubEnv("VITE_PACKAGE", "full");
+    });
+
+    beforeEach(() => {
+      mockConfig({});
+      window.location.hash = "#";
+      PosthogAnalytics.resetInstance();
+    });
+
+    afterAll(() => {
+      vi.unstubAllEnvs();
+    });
+
+    it("does not create instance without config value", () => {
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(false);
+    });
+
+    it("ignores URL params and does not create instance", () => {
+      window.location.hash = `#?posthogApiHost=${encodeURIComponent("https://url.example.com.localhost")}&posthogApiKey=api_key`;
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(false);
+    });
+
+    it("creates instance with config value", () => {
+      mockConfig({
+        posthog: {
+          api_host: "https://api.example.com.localhost",
+          api_key: "api_key",
+        },
+      });
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(true);
+    });
+  });
+});