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/data.ts b/webui/src/data.ts
index 9b5aca9..11e3887 100644
--- a/webui/src/data.ts
+++ b/webui/src/data.ts
@@ -27,6 +27,8 @@
     cache_creation_input_tokens: number;
     total_cost_usd: number;
   };
+  outstanding_llm_calls?: number;
+  outstanding_tool_calls?: string[];
 }
 
 /**