docs(fs): document bounded byte reads

docs/subsystems/filesystem.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 docs/subsystems/filesystem.md
-filesystem.md: b87021630593c85379cbc10af4b0da50ddc7c179
-filesystem.zh.md: 6f4d1441f1bafbe2316003519841a7c9c2c0dbab
+filesystem.md: 01fe2d07f5497374019855ca46ced7e173d21445
+filesystem.zh.md: e68246d7a44b8812e132e02979a2c0cda6adb792

docs/subsystems/filesystem.md

@@ -52,7 +52,7 @@ type FsTargetKey = Branded<'FsTargetKey'>
 type FsVersion = Branded<'FsVersion'>
 ```
 
-`stat` returns metadata (never content), or `undefined` when the target is absent. `type` lets the tool reject directories/special files before reading, and `size` lets it choose `readText` vs `streamText` without probing by failure. A protocol consumer that needs a byte ceiling applies it while consuming `streamText`, so the filesystem seam needs no consumer-specific bounded-read primitive.
+`stat` returns metadata (never content), or `undefined` when the target is absent. `type` lets consumers reject directories and special files before reading, and `size` lets text consumers choose `readText` vs `streamText` without probing by failure. A text consumer applies its own retention ceiling while consuming `streamText`. Raw-byte consumers use `readBytes(target, signal, maxBytes)`; its required complete-content cap makes a known or discovered overflow fail with `FS_TOO_LARGE` instead of truncating or buffering without a bound.
 
 ```ts type-equiv
 /**
@@ -275,7 +275,7 @@ type FsErrorCode =
 
 ## The service and the plugin
 
-`FileSystem` (`ctx.fs`, abstract) owns the provider primitives: `resolve`, `processPath`, `fileUrl`, `contains`, `stat`, `lstat`, `readText`, `streamText`, `listDir`, `writeText`, and `editText`. `dsh-fs-policy` registers **no service** — it is a plugin that adds policy through the `fs/*` event gate: it decides the write/edit intent waterfalls from unseen/absent/present state and records `FsObservation` values. The executor is `dsh-tool-fs`: it reads/writes/edits through `ctx.fs`, dispatches the waterfalls, and emits the recording event. The generated [`ctx.fs` section](#ctxfs--filesystem-abstract-seam) below shows the exact signatures.
+`FileSystem` (`ctx.fs`, abstract) owns the provider primitives: `resolve`, `processPath`, `fileUrl`, `contains`, `stat`, `lstat`, `readText`, `streamText`, `readBytes`, `listDir`, `writeText`, and `editText`. `dsh-fs-policy` registers **no service** — it is a plugin that adds policy through the `fs/*` event gate: it decides the write/edit intent waterfalls from unseen/absent/present state and records `FsObservation` values. The executor is `dsh-tool-fs`: it reads/writes/edits through `ctx.fs`, dispatches the waterfalls, and emits the recording event. The generated [`ctx.fs` section](#ctxfs--filesystem-abstract-seam) below shows the exact signatures.
 
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docs/subsystems/filesystem.zh.md

@@ -52,7 +52,7 @@ type FsTargetKey = Branded<'FsTargetKey'>
 type FsVersion = Branded<'FsVersion'>
 ```
 
-`stat` 返回元数据（从不返回内容），目标不存在时返回 `undefined`。`type` 让工具在读取前拒绝目录或特殊文件；`size` 让工具无需通过失败探测即可选择 `readText` 还是 `streamText`。需要字节上限的协议消费方在消费 `streamText` 时执行该上限，因此文件系统 seam 无需消费方专用的有界读取原语。
+`stat` 返回元数据（从不返回内容），目标不存在时返回 `undefined`。`type` 让消费方在读取前拒绝目录和特殊文件；`size` 让文本消费方无需通过失败探测即可选择 `readText` 还是 `streamText`。文本消费方在消费 `streamText` 时执行自己的保留量上限。原始字节消费方调用 `readBytes(target, signal, maxBytes)`；其必填的完整内容上限会使已知或读取中发现的超限以 `FS_TOO_LARGE` 失败，不会截断结果或无界缓冲。
 
 ```ts type-equiv
 /**
@@ -275,7 +275,7 @@ type FsErrorCode =
 
 ## 服务与插件
 
-`FileSystem`（`ctx.fs`，abstract）拥有提供方原语：`resolve`、`processPath`、`fileUrl`、`contains`、`stat`、`lstat`、`readText`、`streamText`、`listDir`、`writeText` 与 `editText`。`dsh-fs-policy` **不注册服务**——它是一个通过 `fs/*` 事件门禁添加策略的插件：根据未见/缺失/存在状态对写入与编辑意图 waterfall 作出决策，并记录 `FsObservation` 值。执行器是 `dsh-tool-fs`：它通过 `ctx.fs` 读取/写入/编辑，分发 waterfall，并 emit 记录事件。下方生成的 [`ctx.fs` 小节](#ctxfs--filesystem-abstract-seam) 展示确切的 `ctx.fs` 签名。
+`FileSystem`（`ctx.fs`，abstract）拥有提供方原语：`resolve`、`processPath`、`fileUrl`、`contains`、`stat`、`lstat`、`readText`、`streamText`、`readBytes`、`listDir`、`writeText` 与 `editText`。`dsh-fs-policy` **不注册服务**——它是一个通过 `fs/*` 事件门禁添加策略的插件：根据未见/缺失/存在状态对写入与编辑意图 waterfall 作出决策，并记录 `FsObservation` 值。执行器是 `dsh-tool-fs`：它通过 `ctx.fs` 读取/写入/编辑，分发 waterfall，并 emit 记录事件。下方生成的 [`ctx.fs` 小节](#ctxfs--filesystem-abstract-seam) 展示确切的 `ctx.fs` 签名。
 
 <!-- BEGIN GENERATED cordis-surface (gen-cordis-catalog.ts) — do not edit between markers -->