fix(feishu): set client_max_size on the webhook Application

Follow-up to the salvaged #54938: the bounded reader gives a proper 413 +
anomaly telemetry for oversized chunked bodies; client_max_size makes
aiohttp enforce the same 1 MiB cap on every other read path
(#58536/#58902/#59180 pattern). Test fixture's fake Application now
accepts kwargs.

plugins/platforms/feishu/adapter.py

@@ -4747,7 +4747,10 @@ class FeishuAdapter(BasePlatformAdapter):
         if self._event_handler is None:
             raise RuntimeError("failed to build Feishu event handler")
         await self._hydrate_bot_identity()
-        app = web.Application()
+        # client_max_size backstops the bounded reader in
+        # _handle_webhook_request; aiohttp then enforces the same cap on
+        # every read path (#58536/#58902/#59180 pattern).
+        app = web.Application(client_max_size=_FEISHU_WEBHOOK_MAX_BODY_BYTES)
         app.router.add_post(self._webhook_path, self._handle_webhook_request)
         self._webhook_runner = web.AppRunner(app)
         await self._webhook_runner.setup()

tests/gateway/test_feishu.py

@@ -190,7 +190,7 @@ class TestFeishuAdapterMessaging(unittest.TestCase):
         runner = AsyncMock()
         site = AsyncMock()
         web_module = SimpleNamespace(
-            Application=lambda: SimpleNamespace(router=SimpleNamespace(add_post=lambda *_args, **_kwargs: None)),
+            Application=lambda **_kwargs: SimpleNamespace(router=SimpleNamespace(add_post=lambda *_args, **_kwargs: None)),
             AppRunner=lambda _app: runner,
             TCPSite=lambda _runner, host, port: SimpleNamespace(start=site.start, host=host, port=port),
         )