feat(web): migrate billing-client + feature-flags to shared packages

- billing-client.ts: hand-rolled fetch → @bytelyst/subscription-client
  wrapper with backwards-compatible Subscription type adapter
- feature-flags.ts: hand-rolled polling → @bytelyst/feature-flag-client
  (71→42 lines, same public API)
- providers.tsx: remove platform param (now configured at client level)
- ChronoMind-specific usage API stays as local fetch call

web/package-lock.json

@@ -11,7 +11,9 @@
         "@bytelyst/api-client": "file:../../learning_ai_common_plat/packages/api-client",
         "@bytelyst/auth-client": "file:../../learning_ai_common_plat/packages/auth-client",
         "@bytelyst/diagnostics-client": "file:../../learning_ai_common_plat/packages/diagnostics-client",
+        "@bytelyst/feature-flag-client": "file:../../learning_ai_common_plat/packages/feature-flag-client",
         "@bytelyst/react-auth": "file:../../learning_ai_common_plat/packages/react-auth",
+        "@bytelyst/subscription-client": "file:../../learning_ai_common_plat/packages/subscription-client",
         "@bytelyst/telemetry-client": "file:../../learning_ai_common_plat/packages/telemetry-client",
         "@serwist/next": "^9.5.6",
         "date-fns": "^4.1.0",
@@ -66,6 +68,10 @@
         "zod": "^3.22.0"
       }
     },
+    "../../learning_ai_common_plat/packages/feature-flag-client": {
+      "name": "@bytelyst/feature-flag-client",
+      "version": "0.1.0"
+    },
     "../../learning_ai_common_plat/packages/react-auth": {
       "name": "@bytelyst/react-auth",
       "version": "0.1.0",
@@ -84,6 +90,10 @@
         "react": ">=18.0.0"
       }
     },
+    "../../learning_ai_common_plat/packages/subscription-client": {
+      "name": "@bytelyst/subscription-client",
+      "version": "0.1.0"
+    },
     "../../learning_ai_common_plat/packages/telemetry-client": {
       "name": "@bytelyst/telemetry-client",
       "version": "0.1.0"
@@ -449,10 +459,18 @@
       "resolved": "../../learning_ai_common_plat/packages/diagnostics-client",
       "link": true
     },
+    "node_modules/@bytelyst/feature-flag-client": {
+      "resolved": "../../learning_ai_common_plat/packages/feature-flag-client",
+      "link": true
+    },
     "node_modules/@bytelyst/react-auth": {
       "resolved": "../../learning_ai_common_plat/packages/react-auth",
       "link": true
     },
+    "node_modules/@bytelyst/subscription-client": {
+      "resolved": "../../learning_ai_common_plat/packages/subscription-client",
+      "link": true
+    },
     "node_modules/@bytelyst/telemetry-client": {
       "resolved": "../../learning_ai_common_plat/packages/telemetry-client",
       "link": true

web/package.json

@@ -18,6 +18,8 @@
     "@bytelyst/auth-client": "file:../../learning_ai_common_plat/packages/auth-client",
     "@bytelyst/react-auth": "file:../../learning_ai_common_plat/packages/react-auth",
     "@bytelyst/diagnostics-client": "file:../../learning_ai_common_plat/packages/diagnostics-client",
+    "@bytelyst/feature-flag-client": "file:../../learning_ai_common_plat/packages/feature-flag-client",
+    "@bytelyst/subscription-client": "file:../../learning_ai_common_plat/packages/subscription-client",
     "@bytelyst/telemetry-client": "file:../../learning_ai_common_plat/packages/telemetry-client",
     "@serwist/next": "^9.5.6",
     "date-fns": "^4.1.0",

web/src/app/providers.tsx

@@ -13,7 +13,7 @@ export function Providers({ children }: { children: ReactNode }) {
 
   useEffect(() => {
     initTelemetry();
-    initFeatureFlags({ platform: 'web' });
+    initFeatureFlags();
     initDiagnostics();
   }, []);
 

web/src/lib/billing-client.ts

@@ -1,33 +1,32 @@
 /**
- * Billing / Subscription client stub for ChronoMind.
+ * Billing / Subscription client — thin wrapper over @bytelyst/subscription-client.
  *
- * Calls platform-service subscription + usage endpoints via the auth-api base URL.
+ * Delegates subscription operations to the shared package.
+ * Keeps ChronoMind-specific usage API as a local fetch call.
  * Client-side only — uses the stored auth token for authorization.
  */
 
-import { PRODUCT_ID, getBaseUrl } from './auth-api';
+import { createSubscriptionClient } from '@bytelyst/subscription-client';
+import type { SubscriptionDoc } from '@bytelyst/subscription-client';
+import { PRODUCT_ID, getBaseUrl, getAuthClient } from './auth-api';
 
-function getToken(): string | null {
+// ── Shared client ──────────────────────────────────────────────────
-  if (typeof window === 'undefined') return null;
-  return localStorage.getItem('chronomind_access_token');
-}
 
-async function billingFetch<T>(path: string, options?: RequestInit): Promise<T> {
+let _client: ReturnType<typeof createSubscriptionClient> | null = null;
-  const token = getToken();
+
-  const res = await fetch(`${getBaseUrl()}${path}`, {
+function getClient() {
-    ...options,
+  if (!_client) {
-    headers: {
+    _client = createSubscriptionClient({
-      'Content-Type': 'application/json',
+      baseUrl: getBaseUrl(),
-      'x-product-id': PRODUCT_ID,
+      productId: PRODUCT_ID,
-      ...(token ? { Authorization: `Bearer ${token}` } : {}),
+      userId: 'me',
-      ...(options?.headers as Record<string, string>),
+      getAccessToken: () => getAuthClient().getAccessToken() ?? '',
-    },
     });
-  if (!res.ok) throw new Error(`Billing API error: ${res.status}`);
+  }
-  return res.json();
+  return _client;
 }
 
-// ── Types ──────────────────────────────────────────────────────────
+// ── Types (backwards-compatible) ───────────────────────────────────
 
 export interface Subscription {
   id: string;
@@ -44,28 +43,44 @@ export interface Subscription {
   updatedAt: string;
 }
 
+function toSubscription(doc: SubscriptionDoc): Subscription {
+  return {
+    id: doc.id,
+    productId: doc.productId ?? PRODUCT_ID,
+    userId: doc.userId,
+    plan: doc.plan as Subscription['plan'],
+    status: doc.status as Subscription['status'],
+    currentPeriodStart: doc.currentPeriodStart,
+    currentPeriodEnd: doc.currentPeriodEnd,
+    cancelAtPeriodEnd: doc.cancelAtPeriodEnd,
+    stripeCustomerId: doc.stripeCustomerId,
+    stripeSubscriptionId: doc.stripeSubscriptionId,
+    createdAt: doc.createdAt,
+    updatedAt: doc.updatedAt,
+  };
+}
+
 // ── Subscription API ───────────────────────────────────────────────
 
-export async function getMySubscription(userId: string): Promise<Subscription | null> {
+export async function getMySubscription(_userId?: string): Promise<Subscription | null> {
   try {
-    return await billingFetch<Subscription>(`/subscriptions/${userId}`);
+    const doc = await getClient().getMySubscription();
+    return doc ? toSubscription(doc) : null;
   } catch {
     return null;
   }
 }
 
-export async function cancelSubscription(userId: string): Promise<Subscription | null> {
+export async function cancelSubscription(_userId?: string): Promise<Subscription | null> {
   try {
-    return await billingFetch<Subscription>(`/subscriptions/${userId}`, {
+    const doc = await getClient().cancelSubscription();
-      method: 'PUT',
+    return toSubscription(doc);
-      body: JSON.stringify({ cancelAtPeriodEnd: true }),
-    });
   } catch {
     return null;
   }
 }
 
-// ── Usage API ──────────────────────────────────────────────────────
+// ── Usage API (ChronoMind-specific, not in shared client) ──────────
 
 export interface UsageSummary {
   timersCreated: number;
@@ -75,8 +90,17 @@ export interface UsageSummary {
 
 export async function getUsageSummary(userId: string, days = 30): Promise<UsageSummary | null> {
   try {
-    const data = await billingFetch<{ summary: UsageSummary }>(`/usage/summary?userId=${userId}&days=${days}`);
+    const token = getAuthClient().getAccessToken();
-    return data.summary as UsageSummary;
+    const res = await fetch(`${getBaseUrl()}/usage/summary?userId=${userId}&days=${days}`, {
+      headers: {
+        'Content-Type': 'application/json',
+        'x-product-id': PRODUCT_ID,
+        ...(token ? { Authorization: `Bearer ${token}` } : {}),
+      },
+    });
+    if (!res.ok) return null;
+    const data = await res.json() as { summary: UsageSummary };
+    return data.summary;
   } catch {
     return null;
   }

web/src/lib/feature-flags.ts

@@ -1,70 +1,41 @@
 /**
- * Feature flag client — polls platform-service /flags/poll endpoint.
+ * Feature flag client — thin wrapper over @bytelyst/feature-flag-client.
  *
- * Flags are fetched on init and cached in memory. Re-polls on a configurable
+ * Delegates polling and caching to the shared package.
- * interval (default 5 min). Consumers call `isEnabled('flag_key')`.
+ * Preserves the same public API for existing consumers.
  *
  * Privacy: sends userId + platform only. No PII.
  */
 
-import { PRODUCT_ID } from './auth-api';
+import { createFeatureFlagClient } from '@bytelyst/feature-flag-client';
+import { PRODUCT_ID, getBaseUrl } from './auth-api';
 
-const PLATFORM_URL = process.env.NEXT_PUBLIC_PLATFORM_SERVICE_URL ?? 'https://api.chronomind.app';
+const client = createFeatureFlagClient({
-const POLL_INTERVAL_MS = 5 * 60 * 1000; // 5 minutes
+  baseUrl: getBaseUrl(),
-
+  productId: PRODUCT_ID,
-let _flags: Record<string, boolean> = {};
+  platform: 'web',
-let _initialized = false;
+  pollIntervalMs: 5 * 60 * 1000,
-let _intervalId: ReturnType<typeof setInterval> | null = null;
+});
-
-interface PollParams {
-  userId?: string;
-  platform?: string;
-}
-
-async function fetchFlags(params: PollParams): Promise<Record<string, boolean>> {
-  try {
-    const qs = new URLSearchParams();
-    if (params.userId) qs.set('userId', params.userId);
-    if (params.platform) qs.set('platform', params.platform);
-    const res = await fetch(`${PLATFORM_URL}/api/flags/poll?${qs.toString()}`, {
-      headers: { 'x-product-id': PRODUCT_ID },
-    });
-    if (!res.ok) return _flags;
-    const data = await res.json();
-    return (data as { flags: Record<string, boolean> }).flags ?? {};
-  } catch {
-    return _flags;
-  }
-}
 
 /**
  * Initialize the flag client. Call once on app startup.
  * Fetches flags immediately and starts polling.
  */
-export async function initFeatureFlags(params: PollParams = {}): Promise<void> {
+export async function initFeatureFlags(params: { userId?: string } = {}): Promise<void> {
-  if (_initialized) return;
+  await client.init(params);
-  _initialized = true;
-  const pollParams: PollParams = { platform: 'web', ...params };
-  _flags = await fetchFlags(pollParams);
-  _intervalId = setInterval(async () => {
-    _flags = await fetchFlags(pollParams);
-  }, POLL_INTERVAL_MS);
 }
 
 /** Check if a feature flag is enabled. Returns false if not found or not initialized. */
 export function isEnabled(key: string): boolean {
-  return _flags[key] === true;
+  return client.isEnabled(key);
 }
 
 /** Get all currently cached flags. */
 export function getAllFlags(): Readonly<Record<string, boolean>> {
-  return _flags;
+  return client.getAllFlags();
 }
 
 /** Stop polling and reset state. Useful for tests. */
 export function resetFeatureFlags(): void {
-  if (_intervalId) clearInterval(_intervalId);
+  client.stop();
-  _intervalId = null;
-  _flags = {};
-  _initialized = false;
 }