docs: remove flow from target layout model

docs/proposals/module-boundaries.en.md

@@ -53,11 +53,11 @@ column | row | flex | grid
 ```
 
 A Box with multiple children must have an arrangement rule; the target ETAF contract
-defaults that arrangement to `column` (vertical stacking). Users therefore do not
-need a public layout type named `flow`. `flow` is a real ordinary-content layout
-algorithm inside CSS/Ebox; current Ebox marks it with the CSS-like display pair
-`(block flow)` for plain text/content boxes. It is not an ETAF public mode, Component,
-or extra module.
+defaults that arrangement to `column` (vertical stacking). Children are arranged only
+by `column`, `row`, `flex`, or `grid`. `Text` owns text measurement, wrapping, and
+inline runs, so the target model does not need a separate `flow` layout algorithm.
+Current Ebox marks its ordinary content path with `(block flow)`; that is a historical
+implementation marker, not a required target algorithm or module.
 
 `(box "text")` is shorthand for `(box (text "text"))`. ETAF must not expose
 `(box :content "text")`; `:content` remains an Ebox backend field.
@@ -88,7 +88,7 @@ contributions downstream. It does not own Component lifecycle or data requests.
 ### Ebox
 
 Ebox is the layout and rendering engine, not the ETAF Component Runtime. It owns text
-measurement, wrapping, ordinary Box content layout, row/column/flex/grid geometry,
+measurement, wrapping, row/column/flex/grid geometry,
 surface/scroll geometry,
 stable layout snapshots, and render/paint plans. It does not know Components, slots,
 Context, Actions, Behaviors, Data, or Resources.
@@ -165,7 +165,7 @@ last committed result.
 The clean public direction is `Text + Box(layout) + Component`. If concise syntax is
 needed, `row`/`column`/`flex`/`grid` may be introduced as new compiler sugar, but they
 are not compatibility aliases and must not become Runtime Components. `fragment` is
-transparent structure. `spacer` and `flow` are not public ETAF types; `flow` is only
-the current name for the ordinary Box default path. The redesign does not preserve the
-old Host registry names or add a compatibility layer. This target is not implemented
-merely by documenting it.
+transparent structure. `spacer` and `flow` are not public ETAF types; the target Ebox
+may replace the current `(block flow)` marker with ordinary Box/Text paths instead of
+retaining a separate flow branch. The redesign does not preserve the old Host registry
+names or add a compatibility layer. This target is not implemented merely by documenting it.

docs/proposals/module-boundaries.zh.md

@@ -62,10 +62,10 @@ column | row | flex | grid
 ```
 
 普通 `Box` 包含多个子节点时必须有明确的排列规则；目标 ETAF 规定默认排列为
-`column`（纵向堆叠）。因此用户不需要学习另一个叫 `flow` 的公共布局类型。
-`flow` 在 CSS/Ebox 内部确实是普通内容布局算法；当前 Ebox 用 CSS-like display
-pair `(block flow)` 表示它，主要服务普通文本/内容盒。它不是 ETAF 的公共模式、
-Component 或额外模块。
+`column`（纵向堆叠）。子节点只通过 `column`、`row`、`flex` 或 `grid` 排列。
+`Text` 自己负责文字测量、换行和 inline runs，因此目标模型不需要额外的 `flow`
+布局算法。当前 Ebox 用 CSS-like display pair `(block flow)` 表示普通内容路径，
+这是历史实现标记，不是目标架构必须保留的算法或模块。
 
 语义映射大致为：
 
@@ -184,7 +184,7 @@ Ebox 是布局和渲染引擎，不是 ETAF Component Runtime。
 拥有：
 
 - 文本测量、字宽、换行和内容高度；
-- 普通 Box 内容布局，以及 row、column、flex、grid 的几何算法；
+- Text 内容测量和换行，以及 row、column、flex、grid 的几何算法；
 - padding、border、surface、overflow、scroll 和 viewport 几何；
 - 稳定的布局快照、节点 identity、增量几何更新；
 - 从布局结果到后端可提交 Render/Paint plan 的转换。
@@ -396,8 +396,8 @@ text · fragment · container · row · column · stack · flex · grid · space
 
 当前 Renderer 直接把这些名称映射到 Ebox 构造器；Ebox Playground 也直接使用
 自己的布局 API。这只是现状记录，不是目标 API，也不构成必须保留的兼容表面。
-`spacer` 和 `flow` 都不属于目标公共词汇；`flow` 是 Ebox 内部普通内容布局的
-实现路径名称，不是 ETAF 用户需要选择的布局模式。
+`spacer` 和 `flow` 都不属于目标公共词汇；目标 Ebox 可以用普通 Box/Text 路径
+替代当前的 `flow` 标记，不为它保留独立布局分支。
 
 目标演进方向是：