fix: restore proper legacy behavior in webui by using unified /props refresh

Updated assistant message bubbles to show each message's stored model when available,
falling back to the current server model only when the per-message value is missing

When the model selector is disabled, now fetches /props and prioritizes that model name
over chunk metadata, then persists it with the streamed message so legacy mode properly
reflects the backend configuration

Author: ServeurpersoCom

tools/server/webui/src/lib/components/app/chat/ChatMessages/ChatMessageAssistant.svelte

@@ -83,8 +83,8 @@
 	let displayedModel = $derived((): string | null => {
 		if (!currentConfig.showModelInfo) return null;
 
-		if (currentConfig.modelSelectorEnabled) {
-			return message.model ?? null;
+		if (message.model) {
+			return message.model;
 		}
 
 		return serverModel;

tools/server/webui/src/lib/stores/chat.svelte.ts

@@ -368,6 +368,8 @@ class ChatStore {
 		const PROPS_REFRESH_RETRY_DELAY_MS = 1_000;
 		let serverPropsRefreshRequested = false;
 		let lastPropsRefreshAttempt = 0;
+		const currentConfig = config();
+		const preferServerPropsModel = !currentConfig.modelSelectorEnabled;
 
 		const resetPropsRefreshGate = (options?: { immediate?: boolean }) => {
 			serverPropsRefreshRequested = false;
@@ -431,10 +433,19 @@ class ChatStore {
 				});
 		};
 
-		const recordModel = (modelName: string, persistImmediately = true): void => {
+		const recordModel = (modelName: string | null | undefined, persistImmediately = true): void => {
 			ensureServerPropsRefresh();
 
-			const normalizedModel = normalizeModelName(modelName);
+			const serverModelName = serverStore.modelName;
+			const preferredModelSource = preferServerPropsModel
+				? (serverModelName ?? modelName ?? null)
+				: (modelName ?? serverModelName ?? null);
+
+			if (!preferredModelSource) {
+				return;
+			}
+
+			const normalizedModel = normalizeModelName(preferredModelSource);
 
 			if (!normalizedModel || normalizedModel === resolvedModel) {
 				return;
@@ -458,6 +469,31 @@ class ChatStore {
 			}
 		};
 
+		if (preferServerPropsModel) {
+			const hasExistingProps = serverStore.serverProps !== null;
+
+			const updateModelFromServerProps = (persistImmediately = true) => {
+				const currentServerModel = serverStore.modelName;
+
+				if (!currentServerModel) {
+					return;
+				}
+
+				recordModel(currentServerModel, persistImmediately);
+			};
+
+			updateModelFromServerProps(false);
+
+			serverStore
+				.fetchServerProps({ silent: hasExistingProps })
+				.then(() => {
+					updateModelFromServerProps(true);
+				})
+				.catch((error) => {
+					console.warn('Failed to fetch server props before streaming:', error);
+				});
+		}
+
 		slotsService.startStreaming();
 		slotsService.setActiveConversation(assistantMessage.convId);