chore(data): provisionRetry → pointerGuard (résolution de compte barrière-autoritative)

Le polyfill ne fait plus de retry sur la résolution des comptes (désormais gated sur
la barrière first-State du doc-shim). L'app n'injecte plus qu'un micro-garde borné
(pointerGuard) sur la seule lecture du pointeur écrit-une-fois. Aucune mitigation de
fork/retry côté app — cette responsabilité vit entièrement dans le SDK.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/shared/utils/storeRegistry.ts

@@ -53,13 +53,13 @@ configureStoreRegistry({
   },
   // The app maps its identifier handle to the identity id the lib keys on.
   normalizeId: normalizeIdentifier,
-  // Anti-fork bounded retry (real broker): on a fresh page over the persistent
-  // wallet (reconnection under the SAME identity) the shim may not be synced when
-  // the first read fires → 0 rows. Without this, the registry would provision a
-  // NEW account (a fork), so the fresh page reads its own data as empty. The
-  // bounded backoff waits the sync-lag window out before concluding "genuinely
-  // new". Bounded (never an open-ended broker poll).
-  provisionRetry: { attempts: 8, baseMs: 150, maxStepMs: 2000 },
+  // Pointer micro-guard (real broker): the account records now live in a
+  // subscribable doc-shim reached through a well-known write-once pointer triple in
+  // the store-root. The account read is barrier-authoritative (no account retry).
+  // The only residual store-root sync-lag is the pointer read itself — this bounded
+  // guard re-reads JUST that one triple a few times on a cold reconnect. It can never
+  // provision or fork an account. Bounded (never an open-ended broker poll).
+  pointerGuard: { attempts: 8, baseMs: 150, maxStepMs: 2000 },
 });
 
 // --- Re-export the lib's account record + registry surface (unchanged API) ---