refactor: replace overloaded surface terminology

packages/subagent/subagent/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/subagent/subagent/README.md
-README.md: 27b01188cc1663d9cf59d3d24c91b3dbb35bea5a
+README.md: edddb39a2c197eb7c8acb27f5b7f6b8c6016c517
 README.zh.md: e28a8794cfb227dd475ea2b4c42605a90ec7fa1d

packages/subagent/subagent/README.md

@@ -151,4 +151,4 @@ Prefix-stable within a child: the statement never changes during the child's lif
 - **Process-local residency** — the Activation inbox and ownership graph do not coordinate two harness processes; concurrent access to one persistence store still requires a durable mailbox and cross-process lease protocol.
 - **No replay of accepted-but-unlogged messages** — only messages written to the child Session log are reconstructable with the source that supplied them. A crash may lose an accepted initial prompt or follow-up that never reached the log; a later authorized message can cold-resume the child, but the lost message is not replayed automatically.
 - **No durable report mailbox** — reports require a live direct parent and provide acceptance identity rather than exactly-once delivery or a read receipt.
-- **Lifecycle events are observe-only** — a run-affecting `subagent/end` continuation or decision surface waits for a concrete consumer.
+- **Lifecycle events are observe-only** — a run-affecting `subagent/end` continuation or decision API waits for a concrete consumer.

packages/subagent/subagent/src/index.ts

@@ -1,6 +1,6 @@
 /**
  * Service Definition for the subagent capability seam (`ctx.subagents`): a named-provider registry plus a
- * capability-validating asynchronous start surface. Providers establish a
+ * capability-validating asynchronous start API. Providers establish a
  * child before returning its run, so fulfillment is the single publication and
  * ownership-transfer boundary.
  *

packages/subagent/subagent/tests/continuation.spec.ts

@@ -2059,7 +2059,7 @@ describe('continuable lifecycle observation', () => {
   })
 })
 
-describe('continuable public surface', () => {
+describe('continuable public API', () => {
   it('exposes no host authority, residency query, cancellation, steering, or report operation', async () => {
     const { ctx } = await setup([])
     const subagents: Record<string, unknown> = ctx.subagents as unknown as Record<string, unknown>