fix(telemetry): stitch PostHog identities on MemoryClient init

The Python sync/async MemoryClient and the TS MemoryClient were silently
switching their PostHog distinct_id from an anonymous on-disk UUID to the
user's email post-ping, without sending the merge instruction. PostHog
ended up tracking each user as 2-3 disconnected personas (OSS UUID, CLI
anon UUID, email), and only ~4 $create_alias events fired across ~300K
users. The Python CLI does this correctly today; this change ports the
same pattern to MemoryClient.

- mem0/memory/setup.py: make setup_config() idempotent so it backfills a
  top-level user_id for CLI-first users (the CLI writes
  telemetry.anonymous_id, not user_id, which left OSS telemetry silently
  dropped). Add read_anon_ids() and mark_aliased() helpers.
- mem0/memory/telemetry.py: add AnonymousTelemetry.capture_identify() that
  posts a PostHog $identify event with $anon_distinct_id. Add "$identify"
  to _LIFECYCLE_EVENTS so it bypasses the 90% sampling drop.
- mem0/client/main.py: at the end of __init__ for both MemoryClient and
  AsyncMemoryClient, fire $identify for each unaliased anon ID and
  persist telemetry.aliased_to so the alias only happens once per
  (anon_id, email) pair, ever. All telemetry calls swallow exceptions.
- mem0-ts/src/client/telemetry.ts: mirror with captureIdentify().
- mem0-ts/src/client/config.ts (new): node-only readMem0AnonIds() and
  markMem0Aliased() using async dynamic imports of fs/path/os, gated on
  process.versions.node so browsers no-op cleanly.
- mem0-ts/src/client/mem0.ts: call _maybeAliasAnonToEmail() inside
  _initializeClient after ping resolves the email.

Tests cover the matrix (OSS-only, CLI-only, both, already-aliased) plus
failure modes (malformed JSON, read-only fs, posthog errors, browser
env). Telemetry never raises.

mem0-ts/src/client/mem0.ts

@@ -20,7 +20,8 @@ import {
   CreateMemoryExportPayload,
   GetMemoryExportPayload,
 } from "./mem0.types";
-import { captureClientEvent, generateHash } from "./telemetry";
+import { captureClientEvent, generateHash, telemetry } from "./telemetry";
+import { readMem0AnonIds, markMem0Aliased } from "./config";
 import { camelToSnake, camelToSnakeKeys, snakeToCamelKeys } from "./utils";
 import { createExceptionFromResponse, MemoryError } from "../common/exceptions";
 
@@ -118,6 +119,8 @@ export default class MemoryClient {
         this.telemetryId = generateHash(this.apiKey);
       }
 
+      await this._maybeAliasAnonToEmail();
+
       captureClientEvent("init", this, {
         client_type: "MemoryClient",
       }).catch((error: any) => {
@@ -132,6 +135,25 @@ export default class MemoryClient {
     }
   }
 
+  private async _maybeAliasAnonToEmail(): Promise<void> {
+    try {
+      const email = this.telemetryId;
+      if (!email || !email.includes("@")) return;
+      const anonIds = await readMem0AnonIds();
+      if (!anonIds) return;
+      if (anonIds.aliasedTo === email) return;
+      const candidates = [anonIds.oss, anonIds.cli].filter(
+        (id): id is string => !!id && id !== email,
+      );
+      for (const anonId of candidates) {
+        await telemetry.captureIdentify(anonId, email);
+      }
+      await markMem0Aliased(email);
+    } catch (error: any) {
+      console.error("Failed to alias telemetry identity:", error);
+    }
+  }
+
   private _captureEvent(methodName: string, args: any[]) {
     captureClientEvent(methodName, this, {
       success: true,