docs: update README for Graphiti + Neo4j migration

- Replace ZEP_API_KEY with NEO4J_URI/USER/PASSWORD in env var section
- Add Neo4j as a prerequisite with install instructions for macOS/Linux/Windows
- Add EMBEDDING_MODEL note for Gemini API users
- Add migration note: no third-party account needed, free and no rate limits
- Update both Chinese (README.md) and English (README-EN.md) docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README-EN.md

@@ -102,6 +102,24 @@ Click the image to watch MiroFish's deep prediction of the lost ending based on
 | **Node.js** | 18+ | Frontend runtime, includes npm | `node -v` |
 | **Python** | ≥3.11, ≤3.12 | Backend runtime | `python --version` |
 | **uv** | Latest | Python package manager | `uv --version` |
+| **Neo4j** | 5.x Community | Local knowledge graph database | `neo4j --version` |
+
+**Install Neo4j (choose one):**
+
+```bash
+# macOS
+brew install neo4j
+
+# Linux (Debian/Ubuntu)
+# See official docs: https://neo4j.com/docs/operations-manual/current/installation/linux/
+
+# Windows / All platforms
+# Download Neo4j Desktop: https://neo4j.com/download/
+
+# Set password before first start, then launch
+neo4j-admin dbms set-initial-password your_neo4j_password
+neo4j start
+```
 
 #### 1. Configure Environment Variables
 
@@ -122,11 +140,17 @@ LLM_API_KEY=your_api_key
 LLM_BASE_URL=https://dashscope.aliyuncs.com/compatible-mode/v1
 LLM_MODEL_NAME=qwen-plus
 
-# Zep Cloud Configuration
-# Free monthly quota is sufficient for simple usage: https://app.getzep.com/
-ZEP_API_KEY=your_zep_api_key
+# Knowledge Graph — local Neo4j + Graphiti (free, no rate limits)
+NEO4J_URI=bolt://localhost:7687
+NEO4J_USER=neo4j
+NEO4J_PASSWORD=your_neo4j_password
+
+# Embedding model (uncomment if using Gemini API)
+# EMBEDDING_MODEL=gemini-embedding-001
 ```
 
+> **Note:** MiroFish has migrated from Zep Cloud to local **Graphiti + Neo4j**. No third-party account required — completely free with no rate limits.
+
 #### 2. Install Dependencies
 
 ```bash

README.md

@@ -102,6 +102,24 @@ MiroFish 致力于打造映射现实的群体智能镜像，通过捕捉个体
 | **Node.js** | 18+ | 前端运行环境，包含 npm | `node -v` |
 | **Python** | ≥3.11, ≤3.12 | 后端运行环境 | `python --version` |
 | **uv** | 最新版 | Python 包管理器 | `uv --version` |
+| **Neo4j** | 5.x Community | 本地知识图谱数据库 | `neo4j --version` |
+
+**安装 Neo4j（选择适合你的方式）：**
+
+```bash
+# macOS
+brew install neo4j
+
+# Linux (Debian/Ubuntu)
+# 参考官方文档：https://neo4j.com/docs/operations-manual/current/installation/linux/
+
+# Windows / 所有平台
+# 下载 Desktop 版本：https://neo4j.com/download/
+
+# 首次启动前设置密码，然后启动服务
+neo4j-admin dbms set-initial-password your_neo4j_password
+neo4j start
+```
 
 #### 1. 配置环境变量
 
@@ -122,11 +140,19 @@ LLM_API_KEY=your_api_key
 LLM_BASE_URL=https://dashscope.aliyuncs.com/compatible-mode/v1
 LLM_MODEL_NAME=qwen-plus
 
-# Zep Cloud 配置
-# 每月免费额度即可支撑简单使用：https://app.getzep.com/
-ZEP_API_KEY=your_zep_api_key
+# 知识图谱配置（本地 Neo4j + Graphiti，免费无限制）
+# 安装 Neo4j Community Edition：https://neo4j.com/download/
+# macOS 用户：brew install neo4j && neo4j start
+NEO4J_URI=bolt://localhost:7687
+NEO4J_USER=neo4j
+NEO4J_PASSWORD=your_neo4j_password
+
+# Embedding 模型（使用 Gemini API 时取消注释）
+# EMBEDDING_MODEL=gemini-embedding-001
 ```
 
+> **注意：** MiroFish 已从 Zep Cloud 迁移至本地 **Graphiti + Neo4j**，无需注册任何第三方服务，完全免费且无速率限制。
+
 #### 2. 安装依赖
 
 ```bash