Let people name accounts and use the names to tell accounts apart

Connections get an account_name (migration 0039) that the owner sets with
PATCH /api/connections/<id>; the account label stays the account's
identity, so signing in again still finds it. When someone has more than
one account of a service, its tools are listed as "Telegram · <account>"
and the model sees each account's actions under the account's name
(telegram_send_message_alerts_bot) with the account in the description,
instead of _1 and _2. Actions shared by different services are named
after the service. Tools a user renamed keep their name.

docsgpt/api/connector/connections.py

@@ -161,6 +161,21 @@ class ConnectionDetail(Resource):
             return make_response(jsonify({"success": False, "error": "Failed to load connection"}), 500)
         return make_response(jsonify({"success": True, "connection": detail}), 200)
 
+    @api.doc(description="Name an account: {name}. An empty name clears it. Owner only.")
+    def patch(self, connection_id: str):
+        user_id = _user_id()
+        if not user_id:
+            return _unauthorized()
+        name = _json_body().get("name")
+        if not isinstance(name, str) or len(name.strip()) > service.ACCOUNT_NAME_MAX:
+            return _error(f"name must be text of at most {service.ACCOUNT_NAME_MAX} characters", 400)
+        with db_session() as conn:
+            row = _owned(conn, connection_id, user_id)
+            if row is None:
+                return _not_found()
+            connection = service.rename_connection(conn, row, name)
+        return make_response(jsonify({"success": True, "connection": connection}), 200)
+
     @api.doc(
         description=(
             "Remove a connection: {sources: keep | delete, tools: delete | keep}. "