Implement tracking of outstanding LLM and Tool calls

This commit implements a listener pattern between ant.convo and the Agent for tracking outstanding calls.

* Added fields to the Agent struct to track outstanding LLM calls and Tool calls
* Implemented the listener methods to properly track and update these fields
* Added methods to retrieve the counts and names
* Updated the State struct in loophttp.go to expose this information
* Added a unit test to verify the tracking functionality
* Created UI components with lightbulb and wrench icons to display call status
* Added numerical indicators that always show when there are active calls

Co-Authored-By: sketch <hello@sketch.dev>
diff --git a/webui/src/web-components/sketch-container-status.test.ts b/webui/src/web-components/sketch-container-status.test.ts
index 35c52b8..b5e625d 100644
--- a/webui/src/web-components/sketch-container-status.test.ts
+++ b/webui/src/web-components/sketch-container-status.test.ts
@@ -20,6 +20,8 @@
     messages: 0,
     tool_uses: {},
   },
+  outstanding_llm_calls: 0,
+  outstanding_tool_calls: [],
 };
 
 test("render props", async ({ mount }) => {