implemented the history retention feature

### 1. __History Retention Configuration__

- __config.toml__: Added `[HISTORY]` section with `RETENTION_DAYS = 30` setting
- __Backend Integration__: Updated configuration handling to support history retention
- __API Endpoints__: Modified `/api/config` to read/write history retention settings

### 2. __User Interface__

- __Settings Page__: Added "History Settings" section with number input for retention days
- __Real-time Updates__: Settings are saved to config.toml when changed
- __Clear Documentation__: Explains that retention only applies when incognito mode is off

### 3. __Automatic History Cleanup__

- __Background Processing__: Cleanup runs automatically when new chats are created (non-incognito mode)
- __Smart Logic__: Only deletes chats older than configured retention period
- __Complete Cleanup__: Removes both chat records and associated messages
- __Performance Optimized__: Non-blocking background execution

### 4. __Manual Cleanup API__

- __Endpoint__: `POST /api/cleanup-history` for manual cleanup triggers
- __Utility Functions__: Reusable cleanup logic in dedicated utility file

### 5. __Docker Rebuild__

- __Container Rebuild__: Successfully rebuilt the Docker containers with new features
- __Configuration Persistence__: config.toml changes are preserved in Docker volume
- __Application Ready__: The application should now be accessible at [](http://localhost:3000)<http://localhost:3000>

## Key Features:

1. __Incognito Mode Integration__: History retention only applies when incognito mode is OFF
2. __Flexible Configuration__: 0 = keep forever, any positive number = days to retain
3. __Automatic Cleanup__: Runs in background when creating new chats
4. __Manual Control__: API endpoint for manual cleanup triggers
5. __Database Integrity__: Properly removes both chats and associated messages

## Testing the Feature:

1. __Access the Application__: Open [](http://localhost:3000)<http://localhost:3000> in your browser
2. __Configure Settings__: Go to Settings → History Settings → Set retention days
3. __Test Incognito Mode__: Toggle incognito mode on/off to see different behaviors
4. __Create Test Chats__: Create chats in both modes to verify functionality
5. __Manual Cleanup__: Use the `/api/cleanup-history` endpoint to test manual cleanup

src/app/settings/page.tsx

@@ -26,6 +26,7 @@ interface SettingsType {
   customOpenaiApiKey: string;
   customOpenaiApiUrl: string;
   customOpenaiModelName: string;
+  historyRetentionDays: number;
 }
 
 interface InputProps extends React.InputHTMLAttributes<HTMLInputElement> {
@@ -512,6 +513,33 @@ const Page = () => {
               </div>
             </SettingsSection>
 
+            <SettingsSection title="History Settings">
+              <div className="flex flex-col space-y-4">
+                <div className="flex flex-col space-y-1">
+                  <p className="text-black/70 dark:text-white/70 text-sm">
+                    History Retention (Days)
+                  </p>
+                  <p className="text-xs text-black/60 dark:text-white/60">
+                    Number of days to keep chat history when incognito mode is off (0 = keep forever)
+                  </p>
+                  <Input
+                    type="number"
+                    placeholder="30"
+                    min="0"
+                    value={config.historyRetentionDays?.toString() || '30'}
+                    isSaving={savingStates['historyRetentionDays']}
+                    onChange={(e) => {
+                      setConfig((prev) => ({
+                        ...prev!,
+                        historyRetentionDays: parseInt(e.target.value) || 0,
+                      }));
+                    }}
+                    onSave={(value) => saveConfig('historyRetentionDays', parseInt(value) || 0)}
+                  />
+                </div>
+              </div>
+            </SettingsSection>
+
             <SettingsSection title="System Instructions">
               <div className="flex flex-col space-y-4">
                 <Textarea