feat: add Save Session button

- Added 💾 Save button to history header
- saveCurrentSession saves all messages to current session
- If no session exists, creates one with timestamp name
- Saved sessions appear in history list for selection

src/views/SearchView.vue

@@ -31,6 +31,7 @@
           <div class="bkh">
             <span class="bkht">History</span>
             <div class="bkh-actions">
+              <button class="bkh-btn" title="Save Session" @click="saveCurrentSession">💾 Save</button>
               <button class="bkx" @click="showHistory = false">x</button>
             </div>
             <button class="hs-new-btn" @click="handleNewSession">+ New Session</button>
@@ -748,6 +749,45 @@ async function startNewChat() {
   }
 }
 
+async function saveCurrentSession() {
+  if (messages.value.length === 0) {
+    alert('No messages to save')
+    return
+  }
+  
+  // If no current session, create one
+  if (!currentSession.value) {
+    const now = new Date()
+    const timeStr = `${now.getFullYear()}/${(now.getMonth()+1).toString().padStart(2,'0')}/${now.getDate().toString().padStart(2,'0')} ${now.getHours().toString().padStart(2,'0')}:${now.getMinutes().toString().padStart(2,'0')}`
+    const newSession = await createSession(timeStr, mode.value)
+    if (newSession) {
+      setCurrentSession(newSession)
+    }
+  }
+  
+  // Save all messages to current session
+  if (currentSession.value) {
+    for (const msg of messages.value) {
+      if (msg.role === 'user' && msg.query) {
+        await saveMessage(currentSession.value.id, {
+          role: 'user',
+          content: msg.query,
+          mode: msg.mode || mode.value
+        })
+      } else if (msg.role === 'assistant') {
+        await saveMessage(currentSession.value.id, {
+          role: 'assistant',
+          content: msg.message || msg.answer || '',
+          mode: msg.mode || mode.value,
+          results: msg.results
+        })
+      }
+    }
+    await loadSessions()
+    alert('Session saved!')
+  }
+}
+
 function toggleSessionMenu(id: string) {
   activeSessionMenu.value = activeSessionMenu.value === id ? null : id
 }