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/tools/javascript-repl.ts

@@ -44,25 +44,26 @@ export async function executeJavaScript(
 		// Remove the sandbox iframe after execution
 		sandbox.remove();
 
-		// Return plain text output
-		if (!result.success) {
-			// Return error as plain text
-			return {
-				output: `Error: ${result.error?.message || "Unknown error"}\n${result.error?.stack || ""}`,
-			};
-		}
-
 		// Build plain text response
 		let output = "";
 
 		// Add console output - result.console contains { type: string, text: string } from sandbox.js
 		if (result.console && result.console.length > 0) {
 			for (const entry of result.console) {
-				const prefix = entry.type === "error" ? "[ERROR]" : "";
-				output += (prefix ? `${prefix} ` : "") + entry.text + "\n";
+				output += entry.text + "\n";
 			}
 		}
 
+		// Add error if execution failed
+		if (!result.success) {
+			if (output) output += "\n";
+			output += `Error: ${result.error?.message || "Unknown error"}\n${result.error?.stack || ""}`;
+
+			return {
+				output: output.trim(),
+			};
+		}
+
 		// Add return value if present
 		if (result.returnValue !== undefined) {
 			if (output) output += "\n";