Fix console logging and message routing

Console Logging Improvements:
- Changed ConsoleRuntimeProvider to send logs immediately instead of batching
- Track pending send promises and await them in onCompleted callback
- Ensures REPL gets all logs before execution-complete
- Enables real-time console logging for HTML artifacts

Message Routing Fixes:
- Remove "handled" concept from message routing - broadcast all messages to all providers/consumers
- Change handleMessage return type from Promise<boolean> to Promise<void>
- Add debug logging to RuntimeMessageRouter to trace message flow
- Fix duplicate error logging (window error handler now only tracks errors, doesn't log them)

Output Formatting Consistency:
- Remove [LOG], [ERROR] prefixes from console output in both tools
- Show console logs before error messages
- Use "=> value" format for return values in both javascript-repl and browser-javascript
- Remove duplicate "Error:" prefix and extra formatting

Bug Fixes:
- Fix race condition where execution-complete arrived before console logs
- Fix ConsoleRuntimeProvider blocking execution-complete from reaching consumers
- Remove duplicate console log collection from SandboxedIframe
- Fix return value capture by wrapping user code in async function

packages/web-ui/src/components/sandbox/ArtifactsRuntimeProvider.ts

@@ -143,9 +143,9 @@ export class ArtifactsRuntimeProvider implements SandboxRuntimeProvider {
 		};
 	}
 
-	async handleMessage(message: any, respond: (response: any) => void): Promise<boolean> {
+	async handleMessage(message: any, respond: (response: any) => void): Promise<void> {
 		if (message.type !== "artifact-operation") {
-			return false;
+			return;
 		}
 
 		const { action, filename, content, mimeType } = message;
@@ -224,11 +224,8 @@ export class ArtifactsRuntimeProvider implements SandboxRuntimeProvider {
 				default:
 					respond({ success: false, error: `Unknown artifact action: ${action}` });
 			}
-
-			return true;
 		} catch (error: any) {
 			respond({ success: false, error: error.message });
-			return true;
 		}
 	}