proxy,ui: add version endpoint and display version info in UI (#395)

- Add /api/version endpoint to ProxyManager that returns build date, commit hash, and version
- Implement SetVersion method to configure version info in ProxyManager
- Add version info fetching to APIProvider and display in ConnectionStatus component
- Include version info in UI context and update dependencies
- Add tests for version endpoint functionality

ui/src/components/ConnectionStatus.tsx

@@ -2,7 +2,7 @@ import { useAPI } from "../contexts/APIProvider";
 import { useMemo } from "react";
 
 const ConnectionStatusIcon = () => {
-  const { connectionStatus } = useAPI();
+  const { connectionStatus, versionInfo } = useAPI();
 
   const eventStatusColor = useMemo(() => {
     switch (connectionStatus) {
@@ -17,7 +17,7 @@ const ConnectionStatusIcon = () => {
   }, [connectionStatus]);
 
   return (
-    <div className="flex items-center" title={`event stream: ${connectionStatus}`}>
+    <div className="flex items-center" title={`Event Stream: ${connectionStatus ?? 'unknown'}\nAPI Version: ${versionInfo?.version ?? 'unknown'}\nCommit Hash: ${versionInfo?.commit?.substring(0,7) ?? 'unknown'}\nBuild Date: ${versionInfo?.build_date ?? 'unknown'}`}>
       <span className={`inline-block w-3 h-3 rounded-full ${eventStatusColor} mr-2`}></span>
     </div>
   );