feat: add internal event journal

AGENTS.md

@@ -37,6 +37,10 @@ The **only** exception is documentation explicitly designated as Chinese:
 Everything outside that list — including code under `src/`, this file, and all
 other docs — is English.
 
+Do not label a document as `hand-written` unless its contents are actually
+authored and maintained by humans. For agent-authored source-of-truth documents,
+use wording such as `Chinese source` instead.
+
 ### Bilingual research notes
 
 Research notes are bilingual:

README.md

@@ -51,6 +51,12 @@ checks the result to judge. A non-zero exit means the run could not happen at
 all: `1` for missing credentials or an API that kept refusing, `2` for a
 misused command line.
 
+Every Agent Run also writes a replayable internal Event Journal under
+`~/.nanoPyCodeAgent/journals/`. These JSONL files can contain prompts, model
+replies, repository content, and tool results, so treat them as sensitive;
+the directory is user-only (`0700`) and each file is `0600`. Journals are not
+public run output or trajectories, and they are not rotated automatically yet.
+
 #### Run a branch or tagged version
 
 Run an unreleased branch or a specific release tag straight from GitHub:

README.zh-CN.md

@@ -49,6 +49,11 @@ printf "%s" "$TASK" | nanoPyCodeAgent
 完,那该由检查结果的一方去判定。非零退出码表示这次运行根本没能进行:`1` 是缺少
 凭据或 API 持续失败,`2` 是命令行用错了。
 
+每次 Agent Run 还会在 `~/.nanoPyCodeAgent/journals/` 下写入可重放的内部 Event
+Journal。这些 JSONL 文件可能包含提示词、模型回复、仓库内容和工具结果,应按敏感
+数据处理;目录只允许当前用户访问(`0700`),每个文件的权限为 `0600`。Journal 既
+不是公开 run output,也不是 trajectory,目前还不会自动轮转。
+
 #### 运行某个分支或标签版本
 
 直接从 GitHub 运行未发布的分支,或某个具体的发布标签:

docs/changelogs/0.8.x.md

@@ -26,6 +26,12 @@ All notable changes in the **0.8.x** release series are documented here.
   headless CLI through stdin, forwards model credentials and endpoint
   configuration, saves the run log under `/logs/agent/`, and reports the
   installed agent version without adding Harbor to the end-user package.
+- Versioned Native Events and a per-run internal Event Journal. Model, tool,
+  user, and terminal facts are appended as replayable JSONL with stable IDs,
+  producer versions, ordering, UTC timestamps, durations, usage, provider
+  response metadata, and explicit truncation metadata. Journals are stored as
+  sensitive user-only files while the existing text stdout remains unchanged
+  as an event projection.
 
 ### Fixed
 - Declare `httpx` as a direct runtime dependency so clean and containerized

docs/dev_docs/README.md

@@ -0,0 +1,32 @@
+# System Design Documentation
+
+This directory contains the implemented architecture, internal protocols, and
+other system-design contracts of nanoPyCodeAgent. These documents describe the
+system as it exists. Proposals that are still under discussion should be
+clearly marked as RFCs; durable decision rationale belongs in an ADR when the
+choice is costly to reverse or otherwise surprising.
+
+System-design documents are bilingual and split by language:
+
+- [`zh-CN/`](zh-CN/) — **Chinese source** (source of truth)
+- [`en/`](en/) — **English, generated from the Chinese source** (do not edit by
+  hand)
+
+Write or revise the Chinese source first. Before a pull request containing the
+change is opened or updated for review, translate or refresh the entire
+corresponding English file. The agent preparing or landing the pull request
+must report whether the two versions are in sync.
+
+These documents use the domain language defined in [`CONTEXT.md`](../../CONTEXT.md).
+They complement, rather than replace:
+
+- [`../research/`](../research/) for pre-implementation investigation;
+- [`../dev_notes/`](../dev_notes/) for release-series development notes; and
+- [`../superpowers/specs/`](../superpowers/specs/) for implementation plans and
+  design proposals associated with a particular piece of work.
+
+## Documents
+
+- Event Journal Protocol v1:
+  [English](en/event-journal-protocol-v1.md) |
+  [Chinese](zh-CN/event-journal-protocol-v1.md)