Fix list_runs to use offset parameter

Match the router's expected signature and return type.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/run_service.py

@@ -26,7 +26,7 @@ class RunService:
             return None
         return json.loads(data)
 
-    async def list_runs(self, actor_id: str, page: int = 1, limit: int = 20) -> Dict[str, Any]:
+    async def list_runs(self, actor_id: str, offset: int = 0, limit: int = 20) -> list:
         """List runs for a user with pagination."""
         # Get all runs and filter by actor
         # TODO: Use Redis index for efficient filtering
@@ -52,20 +52,7 @@ class RunService:
         all_runs.sort(key=lambda r: r.get("created_at", ""), reverse=True)
 
         # Paginate
-        total = len(all_runs)
-        start = (page - 1) * limit
-        end = start + limit
-        runs = all_runs[start:end]
-
-        return {
-            "runs": runs,
-            "pagination": {
-                "page": page,
-                "limit": limit,
-                "total": total,
-                "has_more": end < total,
-            }
-        }
+        return all_runs[offset:offset + limit]
 
     async def create_run(
         self,