docs: fix README table rendering for /bind syntax

Author: tonyHu08

README.md

@@ -65,7 +65,8 @@ Notes:
 | --- | --- |
 | `/threads` | List recent threads and bind quickly |
 | `/bind latest` | Bind the latest thread |
-| `/bind <index|threadId>` | Bind a specific thread |
+| `/bind <index>` | Bind by list index (from `/threads`) |
+| `/bind <threadId>` | Bind by thread ID |
 | `/current` | Show snapshot of the current bound thread |
 | `/status` | Show bridge status |
 | `/usage` / `/limits` | Show Codex rate limits remaining |
@@ -173,7 +174,8 @@ Codex 在桌面端很强，但它不是“随时随地继续工作”的工具
 | --- | --- |
 | `/threads` | 查看最近会话并快速绑定 |
 | `/bind latest` | 绑定最新会话 |
-| `/bind <编号|threadId>` | 绑定指定会话 |
+| `/bind <编号>` | 按 `/threads` 列表编号绑定 |
+| `/bind <threadId>` | 按 threadId 绑定 |
 | `/current` | 查看当前会话快照 |
 | `/status` | 查看桥接状态 |
 | `/usage` / `/limits` | 查看剩余用量与重置时间 |