C ABI v2: invoke_stage 写回 + ABI 版本对齐核心版本号 (v0.9.0)

- C ABI invoke_stage 增加 result 输出参数，外部插件 stage 回调可将修改后的
  StageContext(RawMessage/LLMText/FinalText/Response/ToolResults) 写回内核
- ABI 标识版本改为字符串 semver 与核心 Version 对齐(ABIVersion="0.9.0")，
  C 层协商用派生整数 CABINum=900(major*100+minor)，不再使用独立数字编码
- version_min 保证 v0.8.x(800) 旧插件向后兼容可加载
- 修复工具循环 zen 兼容补位误伤首轮 system 上下文(仅尾部为 assistant/tool 时补位)
- 更新 README 项目状态说明

README_EN.md

@@ -15,6 +15,7 @@ homed (kernel, zero IO) ← PluginSDK → plugins (all IO capabilities)
 **Separation of Core Domain and Application Domain** — The kernel's responsibilities are limited to LLM orchestration, memory management, and knowledge retrieval; all IO capabilities (message send/receive, file read/write, network requests, hardware interaction, etc.) are implemented by plugins. This separation defines domain boundaries at the Agent framework level, with distinct responsibility scopes for the kernel and plugins.
 
 **Three-Layer Memory Architecture** — Manages information retention in long-running agents through a tiered storage strategy:
+
 - **Context Layer**: Pretrained word embedding / TF-IDF fallback relevance-scored event window, protects last 10 entries, maintains topK context entries
 - **Document Layer**: Temporary memory with automatic cold data sinking, also supports user-initiated submissions
 - **Graph Layer**: SQLite graph database, persists entity relationships and semantic memory, supports distillation pipelines to extract triples from conversations
@@ -171,6 +172,8 @@ External plugin development: see [homeagent-sdk](https://gitcode.com/JianFeeeee/
 
 ## Project Status
 
+**v0.9.0** — C ABI v2: external plugin Stage callbacks can now write back (`invoke_stage` gained a result out-param; plugins may mutate RawMessage/LLMText/ToolResults etc. in OnInput/AfterToolcall/PostAction and have them synced to the core). ABI version now tracks core minor releases (v0.9.x → ABIVersion=2, `version_min=1` keeps old plugins loadable). Also fixes the tool-loop zen-compat placeholder that wrongly fired on first-turn system context tail. The SDK ships an enhanced sanitizer example (bad-UTF-8 / U+FFFD / ANSI-escape scrub across the whole pipeline).
+
 **v0.8.0** — Core is functional, plugin system enhanced. 20+ built-in plugins. External plugin development via [homeagent-sdk](https://gitcode.com/JianFeeeee/homeagent-sdk) repo. Added input channel `NoMemory`/`Cleaner`, `ChannelDef`, plugin disable/enable system (CLI + WebUI), `plugindev` toolchain C ABI `ChannelDef` support.
 
 ## Documentation