Show Qwen3 thinking output in chat as collapsible Reasoning block

Ollama streams message.thinking tokens alongside message.content when
think=True — previously silently dropped. Now forwarded end-to-end.

Backend:
- llm.py: ChatChunk type gains "thinking" variant; stream_chat_with_tools
  yields ChatChunk(type="thinking") for msg.thinking chunks before content
- generation_task.py: thinking chunks emit "thinking_chunk" SSE events
  (not added to content_so_far — not persisted to DB)

Frontend:
- types/chat.ts: Message.thinking?: string (session-only, not from DB)
- stores/chat.ts: streamingThinking ref; thinking_chunk handler accumulates
  chunks; on done, thinking carried into committed Message object then cleared
- ChatMessage.vue: collapsible <details class="thinking-block"> shown for
  messages that have .thinking content (collapsed by default)
- ChatView.vue + ChatPanel.vue: live thinking block in streaming bubble —
  open while only thinking is flowing, auto-collapses when content arrives;
  typing indicator hidden while thinking is active

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

frontend/src/components/ChatMessage.vue

@@ -68,6 +68,10 @@ const timingParts = computed((): string[] => {
             </button>
           </div>
         </div>
+        <details v-if="message.thinking" class="thinking-block">
+          <summary class="thinking-summary">Reasoning</summary>
+          <pre class="thinking-text">{{ message.thinking }}</pre>
+        </details>
         <div class="message-content prose" v-html="rendered"></div>
         <div v-if="message.tool_calls?.length" class="tool-calls">
           <ToolCallCard
@@ -147,6 +151,49 @@ const timingParts = computed((): string[] => {
   color: var(--color-text-muted);
 }
 
+.thinking-block {
+  margin-bottom: 0.5rem;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  overflow: hidden;
+}
+.thinking-summary {
+  padding: 0.25rem 0.5rem;
+  font-size: 0.72rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  color: var(--color-text-muted);
+  cursor: pointer;
+  user-select: none;
+  list-style: none;
+  display: flex;
+  align-items: center;
+  gap: 0.3rem;
+  background: var(--color-bg-secondary);
+}
+.thinking-summary::-webkit-details-marker { display: none; }
+.thinking-summary::before {
+  content: "▶";
+  font-size: 0.6rem;
+  transition: transform 0.15s;
+}
+details[open] .thinking-summary::before {
+  transform: rotate(90deg);
+}
+.thinking-text {
+  margin: 0;
+  padding: 0.5rem;
+  font-size: 0.8rem;
+  line-height: 1.5;
+  color: var(--color-text-secondary);
+  white-space: pre-wrap;
+  word-break: break-word;
+  max-height: 300px;
+  overflow-y: auto;
+  background: var(--color-bg-secondary);
+  border-top: 1px solid var(--color-border);
+}
 .message-content {
   font-size: 0.95rem;
   line-height: 1.55;

frontend/src/components/ChatPanel.vue

@@ -197,8 +197,16 @@ function promoteAutoNote(note: { id: number; title: string }) {
               <div class="message-header">
                 <span class="role-label">{{ settingsStore.assistantName }}</span>
               </div>
+              <details
+                v-if="store.streamingThinking"
+                class="thinking-block"
+                :open="!store.streamingContent"
+              >
+                <summary class="thinking-summary">Reasoning</summary>
+                <pre class="thinking-text">{{ store.streamingThinking }}</pre>
+              </details>
               <div class="message-content prose" v-html="streamingRendered"></div>
-              <span class="typing-indicator"></span>
+              <span v-if="!store.streamingThinking" class="typing-indicator"></span>
             </div>
           </div>
 
@@ -375,7 +383,49 @@ function promoteAutoNote(note: { id: number; title: string }) {
   line-height: 1.55;
   word-break: break-word;
 }
-
+.thinking-block {
+  margin-bottom: 0.5rem;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  overflow: hidden;
+}
+.thinking-summary {
+  padding: 0.25rem 0.5rem;
+  font-size: 0.72rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  color: var(--color-text-muted);
+  cursor: pointer;
+  user-select: none;
+  list-style: none;
+  display: flex;
+  align-items: center;
+  gap: 0.3rem;
+  background: var(--color-bg-secondary);
+}
+.thinking-summary::-webkit-details-marker { display: none; }
+.thinking-summary::before {
+  content: "▶";
+  font-size: 0.6rem;
+  transition: transform 0.15s;
+}
+details[open] .thinking-summary::before {
+  transform: rotate(90deg);
+}
+.thinking-text {
+  margin: 0;
+  padding: 0.5rem;
+  font-size: 0.8rem;
+  line-height: 1.5;
+  color: var(--color-text-secondary);
+  white-space: pre-wrap;
+  word-break: break-word;
+  max-height: 300px;
+  overflow-y: auto;
+  background: var(--color-bg-secondary);
+  border-top: 1px solid var(--color-border);
+}
 .typing-indicator {
   display: inline-block;
   width: 6px;