feat: add collapsible thinking section for intermediate results

- ThinkingSection component with expand/collapse toggle
- Displays intermediate_result from stream in amber-styled panel
- Positioned below orchestration progress indicator
- Updates in real-time as new intermediate results arrive

Closes #9

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

implementation-plans/_index.md

@@ -10,3 +10,4 @@
 | #6    | Message input with send and keyboard shortcuts         | COMPLETED    | [issue-006.md](issue-006.md) |
 | #7    | Streaming response rendering                          | COMPLETED    | [issue-007.md](issue-007.md) |
 | #8    | Orchestration state progress indicator                 | COMPLETED    | [issue-008.md](issue-008.md) |
+| #9    | Intermediate results display                           | COMPLETED    | [issue-009.md](issue-009.md) |

implementation-plans/issue-009.md

@@ -0,0 +1,17 @@
+---
+---
+
+# Issue #9: Intermediate results display
+
+**Status:** COMPLETED
+**Issue:** https://git.shahondin1624.de/llm-multiverse/llm-multiverse-ui/issues/9
+**Branch:** `feature/issue-9-intermediate-results`
+
+## Acceptance Criteria
+
+- [x] Collapsible "thinking" section component
+- [x] Displays intermediate_result content when present in stream
+- [x] Positioned below the orchestration progress indicator
+- [x] Collapsed by default, expandable on click
+- [x] Updates as new intermediate results arrive
+- [x] Visually distinct from final results (muted amber styling)

src/lib/components/ThinkingSection.svelte

@@ -0,0 +1,31 @@
+<script lang="ts">
+	let { content }: { content: string } = $props();
+
+	let expanded = $state(false);
+</script>
+
+{#if content}
+	<div class="mx-4 mb-2">
+		<button
+			type="button"
+			onclick={() => (expanded = !expanded)}
+			class="flex w-full items-center gap-2 rounded-lg bg-amber-50 px-3 py-2 text-left text-sm text-amber-700 hover:bg-amber-100 transition-colors"
+		>
+			<span
+				class="inline-block transition-transform duration-200 {expanded
+					? 'rotate-90'
+					: 'rotate-0'}"
+			>
+				&#9654;
+			</span>
+			<span class="font-medium">Thinking...</span>
+		</button>
+		{#if expanded}
+			<div
+				class="mt-1 rounded-b-lg border border-t-0 border-amber-200 bg-amber-50/50 px-4 py-3 text-sm text-amber-800 whitespace-pre-wrap"
+			>
+				{content}
+			</div>
+		{/if}
+	</div>
+{/if}

src/routes/chat/+page.svelte

@@ -3,6 +3,7 @@
 	import MessageList from '$lib/components/MessageList.svelte';
 	import MessageInput from '$lib/components/MessageInput.svelte';
 	import OrchestrationProgress from '$lib/components/OrchestrationProgress.svelte';
+	import ThinkingSection from '$lib/components/ThinkingSection.svelte';
 	import { processRequest, OrchestratorError } from '$lib/services/orchestrator';
 	import { OrchestrationState } from '$lib/proto/llm_multiverse/v1/orchestrator_pb';
 
@@ -11,10 +12,12 @@
 	let error: string | null = $state(null);
 	let sessionId = $state(crypto.randomUUID());
 	let orchestrationState: OrchestrationState = $state(OrchestrationState.UNSPECIFIED);
+	let intermediateResult: string = $state('');
 
 	async function handleSend(content: string) {
 		error = null;
 		orchestrationState = OrchestrationState.UNSPECIFIED;
+		intermediateResult = '';
 
 		const userMessage: ChatMessage = {
 			id: crypto.randomUUID(),
@@ -37,6 +40,9 @@
 		try {
 			for await (const response of processRequest(sessionId, content)) {
 				orchestrationState = response.state;
+				if (response.intermediateResult) {
+					intermediateResult = response.intermediateResult;
+				}
 				const idx = messages.length - 1;
 				messages[idx] = {
 					...messages[idx],
@@ -69,6 +75,7 @@
 
 	{#if isStreaming}
 		<OrchestrationProgress state={orchestrationState} />
+		<ThinkingSection content={intermediateResult} />
 	{/if}
 
 	{#if isStreaming && messages.length > 0 && messages[messages.length - 1].content === ''}