docs: apply hierarchy across the corpus

packages/session-title/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-title/README.md
-README.md: 64bca8153e566e1590776af511662a873198106e
-README.zh.md: 5ff52211ac975e31845285f99618503cd775eded
+README.md: c2ccc1cd6d329a58f673a9ea5d47ce2f35c9dc41
+README.zh.md: b8df266a861da5cb20a76d0738bba4993218c3d5

packages/session-title/README.md

@@ -2,13 +2,13 @@
 
 English | [中文](README.zh.md)
 
-Durable session-title state, one optional asynchronous provider seam, and two opt-in model-backed implementations. The built-in first-message fallback is part of the service, so every composition can title a session without an auxiliary model call.
+This family derives durable session titles from the session log, with an optional model-backed provider.
 
 | Package | Role | ctx key |
 |---|---|---|
-| [`session-title/`](session-title/README.md) | Log fold, deterministic fallback, provider registry, and refresh API | `ctx.sessionTitle` |
-| [`session-title-llm/`](session-title-llm/README.md) | Shared route, request logging, prompt, timeout, stream, and validation helper | — |
-| [`session-title-first-message-llm/`](session-title-first-message-llm/README.md) | Optional provider using the first eligible human message | registers on `ctx.sessionTitle` |
-| [`session-title-all-messages-llm/`](session-title-all-messages-llm/README.md) | Optional provider using every eligible human message | registers on `ctx.sessionTitle` |
+| [`session-title/`](session-title/README.md) | Owns title state, fallback behavior, provider registration, and refresh | `ctx.sessionTitle` |
+| [`session-title-llm/`](session-title-llm/README.md) | Provides shared model-backed title generation | — |
+| [`session-title-first-message-llm/`](session-title-first-message-llm/README.md) | Titles a session from its first eligible human message | registers on `ctx.sessionTitle` |
+| [`session-title-all-messages-llm/`](session-title-all-messages-llm/README.md) | Titles a session from all eligible human messages | registers on `ctx.sessionTitle` |
 
-Only one provider may register at a time. The shared demo spine mounts the fallback service but leaves both model providers outside default composition, so deployments choose auxiliary cost and retitling cadence explicitly.
+Deployments may register one model-backed provider; the service retains a deterministic fallback when none is present.

packages/session-title/README.zh.md

@@ -1,14 +1,14 @@
-# session-title/：日志支持的会话标题能力家族
+# session-title/：日志支持的会话标题能力族
 
 [English](README.md) | 中文
 
-持久化的会话标题状态、一个可选异步提供方 seam，以及两个由模型支持、可选启用的实现。内置首消息回退属于服务本身，因此任何组合都能在不调用辅助模型的情况下为会话生成标题。
+该包族从会话日志派生持久会话标题，并支持可选的模型后端 provider。
 
-| 包 | 职责 | ctx 键 |
+| 包 | 职责 | ctx key |
 |---|---|---|
-| [`session-title/`](session-title/README.md) | 日志折叠、确定性回退、提供方注册表与刷新 API | `ctx.sessionTitle` |
-| [`session-title-llm/`](session-title-llm/README.md) | 共享路由、请求日志记录、提示词、超时、流与验证辅助模块 | 无 |
-| [`session-title-first-message-llm/`](session-title-first-message-llm/README.md) | 使用第一条符合条件的用户消息的可选提供方 | 注册到 `ctx.sessionTitle` |
-| [`session-title-all-messages-llm/`](session-title-all-messages-llm/README.md) | 使用所有符合条件的用户消息的可选提供方 | 注册到 `ctx.sessionTitle` |
+| [`session-title/`](session-title/README.md) | 负责标题状态、回退行为、provider 注册与刷新 | `ctx.sessionTitle` |
+| [`session-title-llm/`](session-title-llm/README.md) | 提供共享的模型标题生成能力 | — |
+| [`session-title-first-message-llm/`](session-title-first-message-llm/README.md) | 根据第一条合格的人类消息生成会话标题 | 注册到 `ctx.sessionTitle` |
+| [`session-title-all-messages-llm/`](session-title-all-messages-llm/README.md) | 根据所有合格的人类消息生成会话标题 | 注册到 `ctx.sessionTitle` |
 
-同一时间只能注册一个提供方。共享 demo 主干会挂载回退服务，但默认组合不包含两个模型提供方，因此部署会显式选择辅助成本和重新生成标题的节奏。
+部署可注册一个模型后端 provider；未注册时，服务仍提供确定性回退。