docs: README 更新到 SDK 1.2.0（注入行为 / ContextPolicy / 重编要求）

README 此前停在 SDK 1.1.0，而且 1.2.0 的新增接口**一处都没写**。本次补齐：

- 「版本与兼容性」：当前版本改为 1.2.0（需内核 1.2.0+），并新增
  **1.1.x → 1.2.x 必须重编**的说明——接口是纯追加，但插件运行协议升到 2
  （统一共享内存区 fd3 布局改变，不支持滚动升级），旧 plugin.bin 会因协议
  版本不匹配被拒绝（错误明确提示用配套 plugindev 重编，不静默降级）。
  这与 1.0.x→1.1.x「不需重编」形成对照，必须写清楚。
- 新增「注入行为与上下文裁剪（1.2.0）」章节：`InjectOptions{NoMemory,
  ContextPolicy, CleanerName}`、六个 `*Opts` 变体、`ContextPolicyNone`/`Prune`
  取值、以及三条要点（零值等价于旧三参数方法 / 裁剪必须显式声明 /
  裁剪先经注册的 Cleaner）。签名逐个从 sdk/plugin.go 抄录，未凭记忆书写。
- 「示例插件」补一句：release 附带预编译示例 `.hmap` + SHA256SUMS/MANIFEST，
  理由是插件二进制与内核协议绑定，只发工具链容易让人拿旧产物去装而握手失败。

中英双份同步更新。

README.md

@@ -4,7 +4,7 @@ HomeAgent 插件开发 SDK，用于构建与 HomeAgent 平台交互的智能插
 
 ## 版本与兼容性
 
-当前：**SDK 1.1.0**（需要内核 **1.1.1+** 才能用媒体接口；媒体之外的能力内核 1.0.0 即可）。
+当前：**SDK 1.2.0**（需内核 **1.2.0+**）。
 
 **版本号跟随内核的中版本，patch 位恒为 `.0`**：
 
@@ -22,6 +22,50 @@ HomeAgent 插件开发 SDK，用于构建与 HomeAgent 平台交互的智能插
 实测验证：在新内核上直接建链通过，因为握手校验的是 `ProtocolVersion`、不是 SDK 版本）。
 想用新字段时重编即可。
 
+**1.1.x 插件升到 1.2.x：接口纯追加，但必须重编。** 公开接口没有签名变更（新增
+`InjectOptions` 与六个 `*Opts` 变体、`ChannelDef.ContextPolicy`），不调新能力就不受影响；
+但内核的**插件运行协议升到了 2**（统一共享内存区的 fd3 布局改变，**不支持滚动升级**），
+所以 `plugin.bin` 必须用配套的 `plugindev` 重编后与内核**同批**安装——否则握手时协议版本
+不匹配会被拒绝（错误信息会明确提示用配套 plugindev 重编，不会静默降级）。
+
+## 注入行为与上下文裁剪（1.2.0）
+
+「记不记入记忆」与「要不要据此裁剪上下文」这两件事，原先只有 `ToolDef` 能声明；
+1.2.0 起**注入侧也能声明**，并且二者共用同一套语义与取值。
+
+```go
+type InjectOptions struct {
+	NoMemory      bool   // true = 不参与记忆计算（向量化/关键词提取/蒸馏），原文仍留在上下文
+	ContextPolicy string // ""/none = 不裁剪（默认）；prune = 据此裁剪上下文
+	CleanerName   string // 计算层过滤函数名：先经 Cleaner 得到实际有效内容，再计算/裁剪
+}
+
+const (
+	ContextPolicyNone  = "none"
+	ContextPolicyPrune = "prune"
+)
+
+// 六个变体，与旧的三参数方法一一对应，只多一个 opts
+InjectTextOpts(source, channel, text string, opts InjectOptions)
+InjectInterruptTextOpts(source, channel, text string, opts InjectOptions)
+InjectInputSyncOpts(source, channel, text string, opts InjectOptions) string
+InjectInputMediaOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions)
+InjectInputMediaSyncOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions) string
+InjectInterruptMediaOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions)
+```
+
+要点：
+
+- **零值 `InjectOptions{}` 与旧的三参数方法逐键等价**（记入记忆 + 不裁剪）。旧方法保留为
+  零值糖（`InjectText` / `InjectInterruptText` / `InjectTextNoMemory` …），存量插件不改一行、
+  不需重编即可继续调用。
+- **裁剪（`prune`）必须显式声明**：它会归档丢弃低相关事件，是有副作用的行为，故默认关闭。
+  内核只放行 `""` / `none` / `prune`（`ValidContextPolicy`），未声明的取值会被拒。
+- 裁剪前先经该插件注册的 **`Cleaner`**（由 `CleanerName` 指定）拿到实际有效内容，
+  避开「按原文裁剪、按清洗后计算」这种不一致。
+- `ChannelDef` 也有同名 `context_policy`（并且 1.2.0 给它补上了 JSON tag——通道定义要跨进程
+  传给内核，而 `Cleaner` 是函数必须忽略；无 tag 时新增字段会被静默丢掉）。
+
 ## SDK API 接口
 
 ### Plugin 接口
@@ -444,6 +488,11 @@ ctx.Unlock()
 | [rss](example/rss) | Go | RSS 订阅 |
 | [sanitizer](example/sanitizer) | Go | 内容清洗/安全过滤 |
 
+**发版时附带预编译示例产物**：SDK 的 release 除 5 平台 `plugindev` 外，还包含各示例插件的
+`.hmap` 与 `SHA256SUMS`/`MANIFEST.txt`。原因是插件二进制与内核**协议绑定**（`ProtocolVersion`
++ 共享内存区魔数），只发工具链不发示例产物，很容易拿旧产物去装而握手失败——那看起来像
+「插件坏了」而不是「版本不配套」。
+
 ## Remote Device SDK
 
 用于开发**远程设备接入适配器**的 C 语言 SDK，零外部依赖，兼容嵌入式平台。

README_EN.md

@@ -4,7 +4,7 @@ Plugin development SDK for building intelligent plugins that interact with the H
 
 ## Version and Compatibility
 
-Current: **SDK 1.1.0** (the media APIs need kernel **1.1.1+**; everything else works on kernel 1.0.0).
+Current: **SDK 1.2.0** (requires kernel **1.2.0+**).
 
 **The version tracks the kernel's minor version, with the patch position pinned at `.0`**:
 
@@ -25,6 +25,60 @@ in the "plugin calls, kernel implements" direction, so not calling it means not
 because the handshake validates `ProtocolVersion`, not the SDK version). Rebuild only when you want
 the new fields.
 
+**Upgrading a 1.1.x plugin to 1.2.x: the interface is purely additive, but a rebuild is required.**
+No public signature changed (the SDK adds `InjectOptions`, six `*Opts` variants and
+`ChannelDef.ContextPolicy`), so not calling the new capabilities means not being affected — but the
+kernel's **plugin protocol went to 2** (the fd3 layout of the unified shared-memory region changed,
+and **rolling upgrades are not supported**). `plugin.bin` must therefore be rebuilt with the matching
+`plugindev` and installed **together with** the kernel; otherwise the handshake fails on protocol
+version mismatch (the error says explicitly to rebuild with the matching plugindev — it never
+degrades silently).
+
+## Injection Behaviour and Context Pruning (1.2.0)
+
+"Should this go into memory" and "should the context be pruned based on this" used to be
+something only `ToolDef` could declare. Since 1.2.0 **injections can declare them too**, sharing
+the same semantics and values.
+
+```go
+type InjectOptions struct {
+	NoMemory      bool   // true = excluded from memory computation (vectorize/keywords/distill); the
+	                     //        original text still stays in context
+	ContextPolicy string // ""/none = do not prune (default); prune = prune context based on this
+	CleanerName   string // name of the compute-layer cleaner: run it first to get the effective
+	                     // content, then compute/prune on that
+}
+
+const (
+	ContextPolicyNone  = "none"
+	ContextPolicyPrune = "prune"
+)
+
+// Six variants, one-to-one with the older three-argument methods, plus opts
+InjectTextOpts(source, channel, text string, opts InjectOptions)
+InjectInterruptTextOpts(source, channel, text string, opts InjectOptions)
+InjectInputSyncOpts(source, channel, text string, opts InjectOptions) string
+InjectInputMediaOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions)
+InjectInputMediaSyncOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions) string
+InjectInterruptMediaOpts(source, channel, text string, blocks []ContentBlock, opts InjectOptions)
+```
+
+Key points:
+
+- **A zero-valued `InjectOptions{}` is key-for-key equivalent to the older three-argument methods**
+  (recorded in memory, not pruned). The old methods remain as zero-value sugar (`InjectText`,
+  `InjectInterruptText`, `InjectTextNoMemory`, …), so existing plugins keep working without a single
+  line changed *or* a rebuild.
+- **Pruning (`prune`) must be declared explicitly**: it archives/drops low-relevance events, which
+  is a side effect, so it is off by default. The kernel only accepts `""` / `none` / `prune`
+  (`ValidContextPolicy`); anything else is rejected.
+- Pruning first goes through the plugin's registered **`Cleaner`** (named by `CleanerName`) to get
+  the effective content, avoiding the inconsistency of "prune on the raw text, compute on the
+  cleaned text".
+- `ChannelDef` carries the same `context_policy` (1.2.0 also gave `ChannelDef` JSON tags — the
+  definition crosses the process boundary, while `Cleaner` is a function that must be ignored; with
+  no tags, newly added fields would be silently dropped).
+
 ## SDK API Surface
 
 ### Plugin Interface
@@ -422,6 +476,13 @@ Internal plugins (platform built-in) have full SDK access including SocialAPI wr
 | [rss](example/rss) | Go | RSS subscriptions |
 | [sanitizer](example/sanitizer) | Go | Content sanitization / safety filtering |
 
+**Prebuilt example artifacts ship with every release**: besides the 5-platform `plugindev`, an SDK
+release contains the example plugins' `.hmap` files plus `SHA256SUMS`/`MANIFEST.txt`. The reason is
+that plugin binaries are **protocol-bound** to the kernel (`ProtocolVersion` + the shared-memory
+magic), so shipping the toolchain without matching artifacts invites installing an old artifact —
+which fails the handshake and looks like "the plugin is broken" rather than "the versions don't
+match".
+
 ## Remote Device SDK
 
 A C language SDK for developing **remote device access adapters** with zero external dependencies, compatible with embedded platforms.