test: fix event-loop error in capture_wallet no-op test

asyncio.get_event_loop() raises RuntimeError on Python 3.12+ when no
loop is running. Convert the test to async def (asyncio_mode=auto) and
await capture_wallet directly, matching the other async tests in the file.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: vvillait88

tests/test_middleware.py

@@ -299,7 +299,7 @@ def test_no_ops_when_wallet_authenticated(self):
         assert capture_route.call_count == 0
 
     @respx.mock
-    def test_no_ops_when_gate_did_not_run(self):
+    async def test_no_ops_when_gate_did_not_run(self):
         """Calling capture_wallet on a request that never went through AgentScoreGate
         (no middleware installed) should silently no-op rather than crash."""
         import httpx as httpx_client  # avoid shadowing the module-level import
@@ -319,11 +319,7 @@ async def _receive() -> dict:
 
         request = SReq(scope, _receive)
 
-        import asyncio
-
-        asyncio.get_event_loop().run_until_complete(
-            capture_wallet(request, "0xsigner", "evm"),
-        )
+        await capture_wallet(request, "0xsigner", "evm")
         assert capture_route.call_count == 0