fix: shrink images to reported provider dimension limit (#45979)

Parse provider-reported image pixel ceilings so many-image Anthropic requests can recover by shrinking Retina screenshots below the stricter limit instead of retrying the same rejected payload.

run_agent.py

@@ -4553,10 +4553,18 @@ class AIAgent:
         )
         return summary
 
-    def _try_shrink_image_parts_in_messages(self, api_messages: list) -> bool:
+    def _try_shrink_image_parts_in_messages(
+        self,
+        api_messages: list,
+        *,
+        max_dimension: int = 8000,
+    ) -> bool:
         """Forwarder — see ``agent.conversation_compression.try_shrink_image_parts_in_messages``."""
         from agent.conversation_compression import try_shrink_image_parts_in_messages
-        return try_shrink_image_parts_in_messages(api_messages)
+        return try_shrink_image_parts_in_messages(
+            api_messages,
+            max_dimension=max_dimension,
+        )
 
     def _try_strip_image_parts_from_tool_messages(self, api_messages: list) -> bool:
         """Downgrade list-type tool messages to text summaries in-place.