feat: show model name below conversion result

Add muted 'Responded by {model}' line below the output text so the
user knows which LLM produced the result. The model name comes from
the server-side LLM config (OPENAI_MODEL env var, default: llama3)
and is passed through the API response.

src/lib/llm.ts

@@ -21,6 +21,7 @@ export interface ConvertResult {
 	converted: string;
 	publicSystemPrompt: string;
 	publicUserMessage: string;
+	model: string;
 }
 
 const INPUT_TAG_START = '###### USER INPUT START ######';
@@ -102,6 +103,7 @@ export async function convertText(
 	return {
 		converted,
 		publicSystemPrompt: buildPublicSystemPrompt(styleModifier, intensityInstruction),
-		publicUserMessage: text
+		publicUserMessage: text,
+		model: merged.model
 	};
 }

src/lib/types.ts

@@ -24,6 +24,7 @@ export interface ConversionResponse {
 	intensity: number;
 	systemPrompt: string;
 	userMessage: string;
+	model: string;
 }
 
 export interface LLMConfig {

src/routes/+page.svelte

@@ -12,6 +12,7 @@
 	let error = $state('');
 	let systemPrompt = $state('');
 	let userMessage = $state('');
+	let modelName = $state('');
 	let showPrompt = $state(false);
 	let copied = $state(false);
 
@@ -40,6 +41,7 @@
 		outputText = '';
 		systemPrompt = '';
 		userMessage = '';
+		modelName = '';
 		showPrompt = false;
 
 		try {
@@ -63,6 +65,7 @@
 			outputText = result.converted;
 			systemPrompt = result.systemPrompt;
 			userMessage = result.userMessage;
+			modelName = result.model;
 		} catch (err) {
 			error = err instanceof Error ? err.message : 'Something went wrong';
 		} finally {
@@ -185,6 +188,9 @@
 				</button>
 			</div>
 			<div class="output-text">{outputText}</div>
+			{#if modelName}
+				<p class="model-attribution">Responded by {modelName}</p>
+			{/if}
 		</div>
 
 		<div class="prompt-section">
@@ -381,6 +387,13 @@
 		font-size: 1rem;
 	}
 
+	.model-attribution {
+		margin-top: 0.75rem;
+		font-size: 0.8rem;
+		color: #9ca3af;
+		font-style: italic;
+	}
+
 	.prompt-section {
 		margin-top: 1rem;
 	}

src/routes/api/convert/+server.ts

@@ -53,7 +53,8 @@ export const POST: RequestHandler = async ({ request }) => {
 			styleId,
 			intensity,
 			systemPrompt: result.publicSystemPrompt,
-			userMessage: result.publicUserMessage
+			userMessage: result.publicUserMessage,
+			model: result.model
 		};
 
 		return json(response);