webui: introduce OpenAI-compatible model selector in JSON payload (#16562)

* webui: introduce OpenAI-compatible model selector in JSON payload

* webui: restore OpenAI-Compatible model source of truth and unify metadata capture

This change re-establishes a single, reliable source of truth for the active model:
fully aligned with the OpenAI-Compat API behavior

It introduces a unified metadata flow that captures the model field from both
streaming and non-streaming responses, wiring a new onModel callback through ChatService
The model name is now resolved directly from the API payload rather than relying on
server /props or UI assumptions

ChatStore records and persists the resolved model for each assistant message during
streaming, ensuring consistency across the UI and database
Type definitions for API and settings were also extended to include model metadata
and the onModel callback, completing the alignment with OpenAI-Compat semantics

* webui: address review feedback from allozaur

* webui: move model selector into ChatForm (idea by @allozaur)

* webui: make model selector more subtle and integrated into ChatForm

* webui: replaced the Flowbite selector with a native Svelte dropdown

* webui: add developer setting to toggle the chat model selector

* webui: address review feedback from allozaur

Normalized streamed model names during chat updates
by trimming input and removing directory components before saving
or persisting them, so the conversation UI shows only the filename

Forced model names within the chat form selector dropdown to render as
a single-line, truncated entry with a tooltip revealing the full name

* webui: toggle displayed model source for legacy vs OpenAI-Compat modes

When the selector is disabled, it falls back to the active server model name from /props

When the model selector is enabled, the displayed model comes from the message metadata
(the one explicitly selected and sent in the request)

* Update tools/server/webui/src/lib/components/app/chat/ChatForm/ChatFormActions.svelte

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/constants/localstorage-keys.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/components/app/chat/ChatForm/ChatFormModelSelector.svelte

Co-authored-by: Aleksander Grygier <[email protected]>

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

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/services/chat.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/services/chat.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* webui: refactor model selector and persistence helpers

- Replace inline portal and event listeners with proper Svelte bindings
- Introduce 'persisted' store helper for localStorage sync without runes
- Extract 'normalizeModelName' utils + Vitest coverage
- Simplify ChatFormModelSelector structure and cleanup logic

Replaced the persisted store helper's use of '$state/$effect' runes with
a plain TS implementation to prevent orphaned effect runtime errors
outside component context

Co-authored-by: Aleksander Grygier <[email protected]>

* webui: document normalizeModelName usage with inline examples

* Update tools/server/webui/src/lib/components/app/chat/ChatForm/ChatFormModelSelector.svelte

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/stores/models.svelte.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* Update tools/server/webui/src/lib/stores/models.svelte.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* webui: extract ModelOption type into dedicated models.d.ts

Co-authored-by: Aleksander Grygier <[email protected]>

* webui: refine ChatMessageAssistant displayedModel source logic

* webui: stabilize dropdown, simplify model extraction, and init assistant model field

* chore: update webui static build

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

Co-authored-by: Aleksander Grygier <[email protected]>

* chore: npm format, update webui static build

* webui: align sidebar trigger position, remove z-index glitch

* chore: update webui build output

---------

Co-authored-by: Aleksander Grygier <[email protected]>

Author: ServeurpersoCom

tools/server/public/index.html.gz

@@ -3,6 +3,8 @@
 	import { Button } from '$lib/components/ui/button';
 	import ChatFormActionFileAttachments from './ChatFormActionFileAttachments.svelte';
 	import ChatFormActionRecord from './ChatFormActionRecord.svelte';
+	import ChatFormModelSelector from './ChatFormModelSelector.svelte';
+	import { config } from '$lib/stores/settings.svelte';
 	import type { FileTypeCategory } from '$lib/enums/files';
 
 	interface Props {
@@ -26,32 +28,36 @@
 		onMicClick,
 		onStop
 	}: Props = $props();
+
+	let currentConfig = $derived(config());
 </script>
 
-<div class="flex items-center justify-between gap-1 {className}">
-	<ChatFormActionFileAttachments {disabled} {onFileUpload} />
+<div class="flex w-full items-center gap-2 {className}">
+	<ChatFormActionFileAttachments class="mr-auto" {disabled} {onFileUpload} />
+
+	{#if currentConfig.modelSelectorEnabled}
+		<ChatFormModelSelector class="shrink-0" />
+	{/if}
 
-	<div class="flex gap-2">
-		{#if isLoading}
-			<Button
-				type="button"
-				onclick={onStop}
-				class="h-8 w-8 bg-transparent p-0 hover:bg-destructive/20"
-			>
-				<span class="sr-only">Stop</span>
-				<Square class="h-8 w-8 fill-destructive stroke-destructive" />
-			</Button>
-		{:else}
-			<ChatFormActionRecord {disabled} {isLoading} {isRecording} {onMicClick} />
+	{#if isLoading}
+		<Button
+			type="button"
+			onclick={onStop}
+			class="h-8 w-8 bg-transparent p-0 hover:bg-destructive/20"
+		>
+			<span class="sr-only">Stop</span>
+			<Square class="h-8 w-8 fill-destructive stroke-destructive" />
+		</Button>
+	{:else}
+		<ChatFormActionRecord {disabled} {isLoading} {isRecording} {onMicClick} />
 
-			<Button
-				type="submit"
-				disabled={!canSend || disabled || isLoading}
-				class="h-8 w-8 rounded-full p-0"
-			>
-				<span class="sr-only">Send</span>
-				<ArrowUp class="h-12 w-12" />
-			</Button>
-		{/if}
-	</div>
+		<Button
+			type="submit"
+			disabled={!canSend || disabled || isLoading}
+			class="h-8 w-8 rounded-full p-0"
+		>
+			<span class="sr-only">Send</span>
+			<ArrowUp class="h-12 w-12" />
+		</Button>
+	{/if}
 </div>