feat(core-analytics): add IAnalytics interface, types, and NoopAnalytics

Replaces generator placeholder with IAnalytics interface (track, identify,
pageView, flush), AnalyticsAttributeValue + AnalyticsUser types, and
NoopAnalytics implementation. Adds sibling tests covering all four methods
with 100% coverage. All conformance + coverage gates pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

coverage/summary.json

@@ -1,18 +1,18 @@
 {
-  "generatedAt": "2026-05-13T18:36:10.133Z",
-  "commit": "9800fed",
+  "generatedAt": "2026-05-18T11:31:45.093Z",
+  "commit": "80c702e",
   "repo": {
-    "statements": 95.86,
-    "branches": 88.91,
+    "statements": 95.87,
+    "branches": 89.02,
     "functions": 100,
-    "lines": 95.86,
+    "lines": 95.87,
     "counts": {
-      "lf": 3113,
-      "lh": 2984,
-      "brf": 487,
-      "brh": 433,
-      "fnf": 142,
-      "fnh": 142
+      "lf": 3121,
+      "lh": 2992,
+      "brf": 492,
+      "brh": 438,
+      "fnf": 147,
+      "fnh": 147
     }
   },
   "byPackage": {
@@ -44,6 +44,20 @@
         "fnh": 29
       }
     },
+    "@repo/core-analytics": {
+      "statements": 100,
+      "branches": 100,
+      "functions": 100,
+      "lines": 100,
+      "counts": {
+        "lf": 8,
+        "lh": 8,
+        "brf": 5,
+        "brh": 5,
+        "fnf": 5,
+        "fnh": 5
+      }
+    },
     "@repo/marketing-pages": {
       "statements": 95.64,
       "branches": 83.93,

packages/core-analytics/src/analytics.interface.ts

@@ -0,0 +1,21 @@
+export type AnalyticsAttributeValue = string | number | boolean;
+
+export type AnalyticsUser = {
+  id: string;
+};
+
+export interface IAnalytics {
+  track(
+    event: string,
+    attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void;
+  identify(
+    user: AnalyticsUser,
+    attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void;
+  pageView(
+    path: string,
+    attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void;
+  flush(): Promise<void>;
+}

packages/core-analytics/src/index.ts

@@ -1,2 +1,6 @@
-// placeholder — populated by story 01-scaffold-core-analytics-package
-export {};
+export type {
+  AnalyticsAttributeValue,
+  AnalyticsUser,
+  IAnalytics,
+} from "./analytics.interface";
+export { NoopAnalytics } from "./noop-analytics";

packages/core-analytics/src/noop-analytics.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it } from "vitest";
+import { NoopAnalytics } from "@/noop-analytics";
+
+describe("NoopAnalytics", () => {
+  it("track() does not throw with event name only", () => {
+    const analytics = new NoopAnalytics();
+    expect(() => analytics.track("page_viewed")).not.toThrow();
+  });
+
+  it("track() does not throw with event name and attributes", () => {
+    const analytics = new NoopAnalytics();
+    expect(() =>
+      analytics.track("button_clicked", {
+        label: "signup",
+        count: 1,
+        active: true,
+      }),
+    ).not.toThrow();
+  });
+
+  it("identify() does not throw with user only", () => {
+    const analytics = new NoopAnalytics();
+    expect(() => analytics.identify({ id: "user-123" })).not.toThrow();
+  });
+
+  it("identify() does not throw with user and attributes", () => {
+    const analytics = new NoopAnalytics();
+    expect(() =>
+      analytics.identify({ id: "user-123" }, { plan: "pro", trial: false }),
+    ).not.toThrow();
+  });
+
+  it("pageView() does not throw with path only", () => {
+    const analytics = new NoopAnalytics();
+    expect(() => analytics.pageView("/dashboard")).not.toThrow();
+  });
+
+  it("pageView() does not throw with path and attributes", () => {
+    const analytics = new NoopAnalytics();
+    expect(() =>
+      analytics.pageView("/dashboard", { referrer: "/home", duration: 120 }),
+    ).not.toThrow();
+  });
+
+  it("flush() resolves without throwing", async () => {
+    const analytics = new NoopAnalytics();
+    await expect(analytics.flush()).resolves.toBeUndefined();
+  });
+
+  it("flush() returns a Promise", () => {
+    const analytics = new NoopAnalytics();
+    expect(analytics.flush()).toBeInstanceOf(Promise);
+  });
+});

packages/core-analytics/src/noop-analytics.ts

@@ -0,0 +1,23 @@
+import type {
+  AnalyticsAttributeValue,
+  AnalyticsUser,
+  IAnalytics,
+} from "./analytics.interface";
+
+export class NoopAnalytics implements IAnalytics {
+  track(
+    _event: string,
+    _attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void {}
+  identify(
+    _user: AnalyticsUser,
+    _attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void {}
+  pageView(
+    _path: string,
+    _attributes?: Record<string, AnalyticsAttributeValue>,
+  ): void {}
+  flush(): Promise<void> {
+    return Promise.resolve();
+  }
+}