feat: embedding service — Cloudflare Worker + KV cache + Dashscope

- POST /embed: batch text → vector (max 100)
- KV cache: sha256(model+text), content-addressable, no expiry
- Dashscope text-embedding-v3 upstream (1024 dims)
- Bearer token auth
- Health endpoint

Deployed: https://embed.shazhou.workers.dev

README.md

@@ -1,3 +1,44 @@
-# embed
+# Embedding Service
 
-Embedding computation service — text → vector + cache (Cloudflare Worker)
+Text → vector 计算服务，nerve knowledge 的 embedding 后端。
+
+## 接口
+
+```
+POST /embed
+Authorization: Bearer <token>
+
+{
+  "texts": ["chunk 1", "chunk 2"],
+  "model": "text-embedding-v3"
+}
+
+→ 200
+{
+  "embeddings": [[0.012, ...], [0.056, ...]],
+  "model": "text-embedding-v3",
+  "dimensions": 1024,
+  "cached": [false, true]
+}
+```
+
+## 特性
+
+- **缓存**: KV 存储，key = sha256(model + text)，永不过期
+- **上游**: Dashscope text-embedding-v3（可配置）
+- **批量**: 单次最多 100 条
+- **鉴权**: Bearer token
+
+## 开发
+
+```bash
+pnpm install
+pnpm dev       # 本地开发
+pnpm deploy    # 部署到 Cloudflare Workers
+```
+
+## 环境变量（Secrets）
+
+- `AUTH_TOKEN` — 鉴权 token
+- `DASHSCOPE_API_KEY` — Dashscope API key
+- `DEFAULT_MODEL` — 默认模型（可选，默认 text-embedding-v3）