docs(weixin): add setup guide and focused channel tests

README.md

@@ -719,6 +719,55 @@ nanobot gateway
 
 </details>
 
+<details>
+<summary><b>WeChat (微信 / Weixin)</b></summary>
+
+Uses **HTTP long-poll** with QR-code login via the ilinkai personal WeChat API. No local WeChat desktop client is required.
+
+**1. Install the optional dependency**
+
+```bash
+pip install nanobot-ai[weixin]
+```
+
+**2. Configure**
+
+```json
+{
+  "channels": {
+    "weixin": {
+      "enabled": true,
+      "allowFrom": ["YOUR_WECHAT_USER_ID"]
+    }
+  }
+}
+```
+
+> - `allowFrom`: Add the sender ID you see in nanobot logs for your WeChat account. Use `["*"]` to allow all users.
+> - `token`: Optional. If omitted, log in interactively and nanobot will save the token for you.
+> - `stateDir`: Optional. Defaults to nanobot's runtime directory for Weixin state.
+> - `pollTimeout`: Optional long-poll timeout in seconds.
+
+**3. Login**
+
+```bash
+nanobot channels login weixin
+```
+
+Use `--force` to re-authenticate and ignore any saved token:
+
+```bash
+nanobot channels login weixin --force
+```
+
+**4. Run**
+
+```bash
+nanobot gateway
+```
+
+</details>
+
 <details>
 <summary><b>Wecom (企业微信)</b></summary>
 

tests/test_weixin_channel.py

@@ -0,0 +1,127 @@
+import asyncio
+from unittest.mock import AsyncMock
+
+import pytest
+
+from nanobot.bus.queue import MessageBus
+from nanobot.channels.weixin import (
+    ITEM_IMAGE,
+    ITEM_TEXT,
+    MESSAGE_TYPE_BOT,
+    WeixinChannel,
+    WeixinConfig,
+)
+
+
+def _make_channel() -> tuple[WeixinChannel, MessageBus]:
+    bus = MessageBus()
+    channel = WeixinChannel(
+        WeixinConfig(enabled=True, allow_from=["*"]),
+        bus,
+    )
+    return channel, bus
+
+
+@pytest.mark.asyncio
+async def test_process_message_deduplicates_inbound_ids() -> None:
+    channel, bus = _make_channel()
+    msg = {
+        "message_type": 1,
+        "message_id": "m1",
+        "from_user_id": "wx-user",
+        "context_token": "ctx-1",
+        "item_list": [
+            {"type": ITEM_TEXT, "text_item": {"text": "hello"}},
+        ],
+    }
+
+    await channel._process_message(msg)
+    first = await asyncio.wait_for(bus.consume_inbound(), timeout=1.0)
+    await channel._process_message(msg)
+
+    assert first.sender_id == "wx-user"
+    assert first.chat_id == "wx-user"
+    assert first.content == "hello"
+    assert bus.inbound_size == 0
+
+
+@pytest.mark.asyncio
+async def test_process_message_caches_context_token_and_send_uses_it() -> None:
+    channel, _bus = _make_channel()
+    channel._client = object()
+    channel._token = "token"
+    channel._send_text = AsyncMock()
+
+    await channel._process_message(
+        {
+            "message_type": 1,
+            "message_id": "m2",
+            "from_user_id": "wx-user",
+            "context_token": "ctx-2",
+            "item_list": [
+                {"type": ITEM_TEXT, "text_item": {"text": "ping"}},
+            ],
+        }
+    )
+
+    await channel.send(
+        type("Msg", (), {"chat_id": "wx-user", "content": "pong", "media": [], "metadata": {}})()
+    )
+
+    channel._send_text.assert_awaited_once_with("wx-user", "pong", "ctx-2")
+
+
+@pytest.mark.asyncio
+async def test_process_message_extracts_media_and_preserves_paths() -> None:
+    channel, bus = _make_channel()
+    channel._download_media_item = AsyncMock(return_value="/tmp/test.jpg")
+
+    await channel._process_message(
+        {
+            "message_type": 1,
+            "message_id": "m3",
+            "from_user_id": "wx-user",
+            "context_token": "ctx-3",
+            "item_list": [
+                {"type": ITEM_IMAGE, "image_item": {"media": {"encrypt_query_param": "x"}}},
+            ],
+        }
+    )
+
+    inbound = await asyncio.wait_for(bus.consume_inbound(), timeout=1.0)
+
+    assert "[image]" in inbound.content
+    assert "/tmp/test.jpg" in inbound.content
+    assert inbound.media == ["/tmp/test.jpg"]
+
+
+@pytest.mark.asyncio
+async def test_send_without_context_token_does_not_send_text() -> None:
+    channel, _bus = _make_channel()
+    channel._client = object()
+    channel._token = "token"
+    channel._send_text = AsyncMock()
+
+    await channel.send(
+        type("Msg", (), {"chat_id": "unknown-user", "content": "pong", "media": [], "metadata": {}})()
+    )
+
+    channel._send_text.assert_not_awaited()
+
+
+@pytest.mark.asyncio
+async def test_process_message_skips_bot_messages() -> None:
+    channel, bus = _make_channel()
+
+    await channel._process_message(
+        {
+            "message_type": MESSAGE_TYPE_BOT,
+            "message_id": "m4",
+            "from_user_id": "wx-user",
+            "item_list": [
+                {"type": ITEM_TEXT, "text_item": {"text": "hello"}},
+            ],
+        }
+    )
+
+    assert bus.inbound_size == 0