refactor: replace overloaded surface terminology

packages/session/session-persistence/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/session/session-persistence/README.md
-README.md: 324c00b3202bd136566137e1bd398b29d2ea4b82
+README.md: c6875dbcfecdfd6ba4eb46d75feca1fbc6fc956d
 README.zh.md: 2ef5e9a90f0323f8edf8fdc4f936c41ca7e08c70

packages/session/session-persistence/README.md

@@ -78,6 +78,6 @@ Persistence does not mutate live request prefixes. A resumed loop can reuse prov
 
 ## Known Limitations and Deferred Work
 
-- **No deletion or retention surface** — pruning stored sessions is out-of-band backend maintenance.
+- **No deletion or retention API** — pruning stored sessions is out-of-band backend maintenance.
 - **`list()` is unpaginated and unfiltered** — it returns every stored session's header; fine for local stores, unindexed at scale.
 - **Repair-time synthetic closers are the only crash story** — a backend must synthesize `tool/result`/`step/end`/`turn/end` closers on load; there is no partial-turn resume that continues an interrupted turn instead of closing it.

packages/session/session-persistence/src/coordinator.ts

@@ -624,7 +624,7 @@ export class PersistenceCoordinator<TornMarker = unknown> {
     this.installWritePath()
   }
 
-  // --- public surface (the backend's service methods delegate here) ---
+  // --- Public API (the backend's service methods delegate here) ---
 
   /**
    * Register detached session metadata for lazy creation on the first append.

packages/session/session-persistence/tests/persistence.spec.ts

@@ -85,7 +85,7 @@ class MemoryPersistence extends SessionPersistence implements PersistenceBackend
     this.coordinator = new PersistenceCoordinator<never>(this.ctx, this)
   }
 
-  // --- service surface (delegated to the coordinator) ---
+  // --- Service API (delegated to the coordinator) ---
 
   locate(_meta: SessionHeader): undefined {
     return undefined