docs: define a seam as the (Service, Service provider, Consumer) trio

packages/bash/bash/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/bash/bash/README.md
-README.md: 690f4e61740faf2648ecbc7f5995ec0fdaa64aee
-README.zh.md: f8bcfce06a406eb94a2486e9825f2beb11b8fd5e
+README.md: e142a796e94dab4ecaa67b8dfce0be4f554f26c0
+README.zh.md: 24a44b418a675d863551642f2edb1f655a2705ab

packages/bash/bash/README.md

@@ -2,7 +2,7 @@
 
 English | [中文](README.zh.md)
 
-The **bash executor seam**: an abstract `BashExecutor` service (`ctx.bash`) defining WHAT a bash backend does — run foreground commands and start background processes — without saying HOW. Task ids, ownership, collection, cancellation, and notices belong to the generic `ctx.tasks` runtime.
+The **`BashExecutor`** (`ctx.bash`) defines WHAT a bash backend does — run foreground commands and start background processes — without saying HOW. Task ids, ownership, collection, cancellation, and notices belong to the generic `ctx.tasks` runtime.
 
 This package is the interface quarter of the bash capability, split so each concern can evolve (and be swapped) independently:
 

packages/bash/bash/README.zh.md

@@ -2,7 +2,7 @@
 
 [English](README.md) | 中文
 
-**bash 执行器 seam**：抽象 `BashExecutor` 服务（`ctx.bash`）定义 bash 后端做什么，即运行前台命令与启动后台进程，但不规定如何实现。task id、所有权、收集、取消与通知属于通用 `ctx.tasks` 运行时。
+**`BashExecutor`**（`ctx.bash`）定义 bash 后端做什么，即运行前台命令与启动后台进程，但不规定如何实现。task id、所有权、收集、取消与通知属于通用 `ctx.tasks` 运行时。
 
 本包是 bash 能力中负责接口的四分之一，各项职责因此可以独立演进（和替换）：