fix(integrations): 扫码确认后不再 500，回话不带链接，栏目改叫「机器人」

1. 扫码确认那一刻页面报「服务器内部错误」：`bot_channel` 的轮询口子直接
   `current_setting('app.bot_channel', true)::uuid`，而事务级 set_config 提交后
   会把连接上的变量还原成空串而不是 NULL，空串 cast 就 InvalidTextRepresentation。
   迁移 0015 改成 nullif(...,'')::uuid，与 app_ws_id() 同一写法。
2. 微信回话只回「已保存任务：…」／「已保存知识草稿：…」，不再带站点链接
   （PUBLIC_BASE_URL 是内网地址，手机上打不开）。
3. 栏目名「接入」改名「机器人」；页面标题与提示文案同步。

pytest 151 passed；ruff check/format 干净；tsc 0；vite build 通过；
web/e2e/integrations.mjs 7 项全绿。

backend/alembic/versions/0015_bot_channel_policy_nullif.py

@@ -0,0 +1,56 @@
+"""bot_channel 的轮询口子要容忍"空字符串"的 GUC
+
+`set_config(..., true)` 提交后会把变量还原成上一次的值；连接池里这条连接如果本来没有
+会话级值，还原出来的是空串 `''` 而不是 NULL。`0014` 的策略直接
+`current_setting('app.bot_channel', true)::uuid`，空串一 cast 就
+`InvalidTextRepresentationError: invalid input syntax for type uuid: ""`，
+于是同一连接上下一个请求（比如扫码确认）500。
+
+这里把策略重建成和 `app_ws_id()` 一样的写法：先 `nullif(..., '')` 再 cast。
+
+Revision ID: 0015
+Revises: 0014
+"""
+
+from __future__ import annotations
+
+from alembic import op
+
+from app.roles import APP_ROLE
+
+revision = "0015"
+down_revision = "0014"
+branch_labels = None
+depends_on = None
+
+STATEMENTS: tuple[str, ...] = (
+    "DROP POLICY IF EXISTS bot_channel_worker ON bot_channel",
+    """
+    CREATE POLICY bot_channel_worker ON bot_channel
+    FOR ALL
+    USING (
+      id = nullif(current_setting('app.bot_channel', true), '')::uuid
+    )
+    WITH CHECK (
+      id = nullif(current_setting('app.bot_channel', true), '')::uuid
+    )
+    """,
+    f"GRANT SELECT, INSERT, UPDATE, DELETE ON bot_channel TO {APP_ROLE}",
+)
+
+
+def upgrade() -> None:
+    for statement in STATEMENTS:
+        op.execute(statement)
+
+
+def downgrade() -> None:
+    op.execute("DROP POLICY IF EXISTS bot_channel_worker ON bot_channel")
+    op.execute(
+        """
+        CREATE POLICY bot_channel_worker ON bot_channel
+        FOR ALL
+        USING (id = current_setting('app.bot_channel', true)::uuid)
+        WITH CHECK (id = current_setting('app.bot_channel', true)::uuid)
+        """
+    )

backend/app/services/wechat_intake.py

@@ -166,18 +166,15 @@ async def create_knowledge(
     return item
 
 
-def item_link(base_url: str, ws_id: uuid.UUID, item: Item) -> str:
-    """给人点的链接。`base_url` 传站点根（http://host:8200），不带 /api/v1。"""
-    base = base_url.rstrip("/")
-    if item.kind == "knowledge":
-        return f"{base}/w/{ws_id}/knowledge/{item.id}"
-    return f"{base}/w/{ws_id}?open={item.id}"
+def reply_text(kind: str, item: Item) -> str:
+    """回话只说"收下了"，不带链接。
 
-
-def reply_text(kind: str, item: Item, link: str) -> str:
+    链接是站点地址，可"站点地址"对手机不一定打得开（内网 IP、端口、还没上 HTTPS 的域名），
+    发过去反而像坏消息。要看详情回网页里看就行。
+    """
     if kind == "knowledge":
-        return f"已存成知识草稿：{item.title}\n{link}"
-    return f"已记下任务：{item.title}\n{link}"
+        return f"已保存知识草稿：{item.title}"
+    return f"已保存任务：{item.title}"
 
 
 async def handle_text(
@@ -208,7 +205,7 @@ async def handle_text(
         return {
             "action": "knowledge",
             "item_id": item.id,
-            "reply": reply_text("knowledge", item, item_link(base_url, channel.workspace_id, item)),
+            "reply": reply_text("knowledge", item),
         }
     item = await create_task(
         session,
@@ -221,5 +218,5 @@ async def handle_text(
     return {
         "action": "task",
         "item_id": item.id,
-        "reply": reply_text("task", item, item_link(base_url, channel.workspace_id, item)),
+        "reply": reply_text("task", item),
     }

backend/tests/test_wechat_bot.py

@@ -176,7 +176,9 @@ async def test_plain_text_becomes_task(client: AsyncClient) -> None:
         await session.commit()
 
     assert result["action"] == "task"
-    assert "已记下任务" in result["reply"]
+    # 回话里只确认"收下了"，不带站点链接（站点地址在手机上不一定打得开）
+    assert result["reply"] == "已保存任务：给客户回电话"
+    assert "http" not in result["reply"]
     async with SessionFactory() as session:
         await bind_tenant(session, ws_id, uuid.UUID(user["user_id"]))
         item = await session.get(Item, result["item_id"])
@@ -207,6 +209,7 @@ async def test_knowledge_prefix_creates_draft_with_tags(client: AsyncClient) ->
         await session.commit()
 
     assert result["action"] == "knowledge"
+    assert result["reply"] == "已保存知识草稿：回滚前先停灰度"
     async with SessionFactory() as session:
         await bind_tenant(session, ws_id, uuid.UUID(user["user_id"]))
         item = await session.get(Item, result["item_id"])
@@ -279,7 +282,7 @@ async def test_poller_handles_message_once_and_replies(
 
     assert len(replies) == 1
     assert replies[0][0] == "wx-user-9"
-    assert "已记下任务" in replies[0][1]
+    assert replies[0][1] == "已保存任务：整理一下本周排期"
 
     async with SessionFactory() as session:
         await session.execute(