Fix Transmission remote connection issues

- Prevent remote host from defaulting to localhost
- Preserve remote connection settings during config updates
- Handle empty values correctly to avoid overriding good config

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

modules/transmission-client.js

@@ -39,8 +39,11 @@ class TransmissionClient {
     const { host, port, username, password, path: rpcPath } = this.config.transmissionConfig;
     
     try {
+      // Only default to localhost if host is empty/null/undefined
+      const connectionHost = (host === undefined || host === null || host === '') ? 'localhost' : host;
+      
       this.client = new Transmission({
-        host: host || 'localhost',
+        host: connectionHost,
         port: port || 9091,
         username: username || '',
         password: password || '',
@@ -48,7 +51,7 @@ class TransmissionClient {
         timeout: 30000 // 30 seconds
       });
       
-      console.log(`Initialized Transmission client connection to ${host}:${port}${rpcPath}`);
+      console.log(`Initialized Transmission client connection to ${connectionHost}:${port}${rpcPath}`);
     } catch (error) {
       console.error('Failed to initialize Transmission client:', error);
       throw error;

server.js

@@ -468,9 +468,45 @@ app.post('/api/config', authenticateJWT, async (req, res) => {
     // Merge the new config with the existing one
     const newConfig = { ...config, ...req.body };
     
-    // Keep passwords if they're not provided
-    if (newConfig.transmissionConfig && !newConfig.transmissionConfig.password && config.transmissionConfig) {
-      newConfig.transmissionConfig.password = config.transmissionConfig.password;
+    // Preserve existing Transmission configuration values when not explicitly provided
+    if (newConfig.transmissionConfig && config.transmissionConfig) {
+      // First create a copy of the existing configuration
+      const preservedTransConfig = { ...config.transmissionConfig };
+      
+      // Only update values that are explicitly provided and not empty
+      if (!req.body.transmissionConfig?.host) {
+        newConfig.transmissionConfig.host = preservedTransConfig.host;
+      }
+      
+      if (!req.body.transmissionConfig?.port) {
+        newConfig.transmissionConfig.port = preservedTransConfig.port;
+      }
+      
+      if (!req.body.transmissionConfig?.path) {
+        newConfig.transmissionConfig.path = preservedTransConfig.path;
+      }
+      
+      if (!req.body.transmissionConfig?.username) {
+        newConfig.transmissionConfig.username = preservedTransConfig.username;
+      }
+      
+      // Always preserve password if not provided
+      if (!newConfig.transmissionConfig.password) {
+        newConfig.transmissionConfig.password = preservedTransConfig.password;
+      }
+    }
+    
+    // Preserve remote configuration settings if not explicitly provided
+    if (newConfig.remoteConfig && config.remoteConfig) {
+      // Make sure isRemote setting is preserved if not explicitly set
+      if (req.body.remoteConfig?.isRemote === undefined) {
+        newConfig.remoteConfig.isRemote = config.remoteConfig.isRemote;
+      }
+      
+      // Preserve directory mappings if not provided
+      if (!req.body.remoteConfig?.directoryMapping && config.remoteConfig.directoryMapping) {
+        newConfig.remoteConfig.directoryMapping = { ...config.remoteConfig.directoryMapping };
+      }
     }
     
     // Keep user passwords