plan(SP22): Task 7 — replace assert with RuntimeError in list_*_acks methods

docs/superpowers/plans/2026-06-21-cyclone-pipeline-agent.md

@@ -1370,7 +1370,8 @@ Add the methods to the `CycloneClient` class:
 
 ```python
     async def list_ta1_acks(self, since: str) -> list[Ta1Ack]:
-        assert self._http is not None
+        if self._http is None:
+            raise RuntimeError("use `async with CycloneClient(...)`")
         resp = await self._http.get(
             "/api/ta1-acks", params={"since": since}
         )
@@ -1381,7 +1382,8 @@ Add the methods to the `CycloneClient` class:
         ]
 
     async def list_acks(self, since: str) -> list[Ack999]:
-        assert self._http is not None
+        if self._http is None:
+            raise RuntimeError("use `async with CycloneClient(...)`")
         resp = await self._http.get(
             "/api/acks", params={"since": since}
         )
@@ -1394,7 +1396,8 @@ Add the methods to the `CycloneClient` class:
     async def list_remittances(
         self, since: str
     ) -> list[RemittanceSummary]:
-        assert self._http is not None
+        if self._http is None:
+            raise RuntimeError("use `async with CycloneClient(...)`")
         resp = await self._http.get(
             "/api/remittances", params={"since": since}
         )