Add settings toggle for previous-conversation context (#66).

Wire Account Preferences to use_conversation_context via preferences API,
with tooltip copy plus loading and error handling on update.

llm-fe/src/llm-fe/components/ThemeSettingsCard/ThemeSettingsCard.tsx

@@ -1,5 +1,7 @@
 import React, { useContext, useEffect, useState } from 'react';
 import styled from 'styled-components';
+import Tooltip from '@mui/material/Tooltip';
+import InfoOutlined from '@mui/icons-material/InfoOutlined';
 import {
   useMaterialUIController,
   setDarkMode,
@@ -48,6 +50,16 @@ const SettingLabel = styled.span`
   font-size: 1.1rem;
   color: ${({ theme }) => theme.colors.text};
   font-weight: 500;
+  display: inline-flex;
+  align-items: center;
+  gap: 0.4rem;
+`;
+
+const InfoIcon = styled(InfoOutlined)`
+  font-size: 1rem !important;
+  opacity: 0.7;
+  cursor: help;
+  vertical-align: middle;
 `;
 
 const ToggleSwitch = styled.label`
@@ -93,6 +105,11 @@ const Checkbox = styled.input`
   &:checked + ${Slider}:before {
     transform: translateX(26px);
   }
+
+  &:disabled + ${Slider} {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
 `;
 
 const ColorPickerContainer = styled.div`
@@ -115,6 +132,23 @@ const ColorButton = styled.button<{ color: string; isSelected: boolean }>`
   }
 `;
 
+const ErrorText = styled.p`
+  color: #ff6b6b;
+  margin: 0.75rem 0 0 0;
+  font-size: 0.95rem;
+`;
+
+const CONTEXT_TOOLTIP =
+  'This will use previous conversations to better customize the experience.';
+
+function prefsErrorMessage(error: unknown, fallback: string): string {
+  const axiosError = error as {
+    response?: { data?: { detail?: string } };
+    message?: string;
+  };
+  return axiosError.response?.data?.detail || axiosError.message || fallback;
+}
+
 type PreferencesValues = {
   order: boolean;
 }
@@ -128,6 +162,10 @@ const ThemeSettingsCard = (): JSX.Element => {
   const themeColors = Object.keys(palettes);
 
   const [order, setOrder] = useState<boolean>(true);
+  const [useConversationContext, setUseConversationContext] = useState<boolean>(false);
+  const [prefsLoading, setPrefsLoading] = useState<boolean>(true);
+  const [contextSaving, setContextSaving] = useState<boolean>(false);
+  const [prefsError, setPrefsError] = useState<string>('');
   const { updatePreferences } = useContext(PreferenceContext);
 
   const handleConversationOrder = async ({ order }: PreferencesValues): Promise<void> => {
@@ -141,17 +179,50 @@ const ThemeSettingsCard = (): JSX.Element => {
     }
   }
 
-  async function getConversationOrder() {
+  async function getConversationPreferences() {
+    setPrefsLoading(true);
+    setPrefsError('');
     try {
-      const { data, }: AxiosResponse<PreferencesType> = await axiosInstance.get(`/conversation_preferences`);
+      const { data }: AxiosResponse<PreferencesType> = await axiosInstance.get(
+        `/conversation_preferences`
+      );
       setOrder(data.order);
+      setUseConversationContext(Boolean(data.use_conversation_context));
     } catch (error) {
-      console.log(error)
+      setPrefsError(
+        prefsErrorMessage(error, 'Could not load account preferences.')
+      );
+    } finally {
+      setPrefsLoading(false);
     }
   }
 
+  const handleConversationContext = async (enabled: boolean): Promise<void> => {
+    const previous = useConversationContext;
+    setUseConversationContext(enabled);
+    setContextSaving(true);
+    setPrefsError('');
+    try {
+      const { data }: AxiosResponse<PreferencesType> = await axiosInstance.post(
+        '/conversation_preferences',
+        { use_conversation_context: enabled }
+      );
+      setUseConversationContext(Boolean(data.use_conversation_context));
+    } catch (error) {
+      setUseConversationContext(previous);
+      setPrefsError(
+        prefsErrorMessage(
+          error,
+          'Could not update conversation context setting. Try again.'
+        )
+      );
+    } finally {
+      setContextSaving(false);
+    }
+  };
+
   useEffect(() => {
-    getConversationOrder();
+    getConversationPreferences();
   }, [])
 
   const handleDarkMode = () => setDarkMode(dispatch, !darkMode);
@@ -193,6 +264,7 @@ const ThemeSettingsCard = (): JSX.Element => {
           <Checkbox
             type="checkbox"
             checked={order}
+            disabled={prefsLoading}
             onChange={() => {
               setOrder(!order);
               handleConversationOrder({ order: !order })
@@ -202,6 +274,30 @@ const ThemeSettingsCard = (): JSX.Element => {
         </ToggleSwitch>
       </SettingRow>
 
+      <SettingRow>
+        <SettingLabel>
+          Use previous conversations
+          <Tooltip title={CONTEXT_TOOLTIP}>
+            <span>
+              <InfoIcon aria-label={CONTEXT_TOOLTIP} />
+            </span>
+          </Tooltip>
+        </SettingLabel>
+        <ToggleSwitch>
+          <Checkbox
+            type="checkbox"
+            checked={useConversationContext}
+            disabled={prefsLoading || contextSaving}
+            onChange={() => {
+              handleConversationContext(!useConversationContext);
+            }}
+          />
+          <Slider />
+        </ToggleSwitch>
+      </SettingRow>
+
+      {prefsError ? <ErrorText role="alert">{prefsError}</ErrorText> : null}
+
     </GlassCard>
   );
 };

llm-fe/src/llm-fe/data.ts

@@ -269,6 +269,7 @@ export interface AccountType {
 
 export interface PreferencesType {
     order: boolean;
+    use_conversation_context?: boolean;
 }
 
 export class Account {