fix: clean up empty catch blocks in frontend components

修复了前端组件中的空 catch 块：
- Tunnel.tsx: 修复空 catch 块并添加注释
- ServerConfig.tsx: 修复空 catch 块并添加注释
- TerminalKeyboard.tsx: 修复空 catch 块并添加注释
- system-crypto.ts: 修复遗漏的空 catch 块

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/backend/utils/system-crypto.ts

@@ -76,7 +76,9 @@ class SystemCrypto {
           process.env.DATABASE_KEY = dbKeyMatch[1];
           return;
         }
-      } catch {}
+      } catch {
+        // Ignore file read errors, will generate new key
+      }
 
       await this.generateAndGuideDatabaseKey();
     } catch (error) {

src/ui/Desktop/Apps/Tunnel/Tunnel.tsx

@@ -191,7 +191,8 @@ export function Tunnel({ filterHostKey }: SSHTunnelProps): React.ReactElement {
       }
 
       await fetchTunnelStatuses();
-    } catch (err) {
+    } catch {
+      // Ignore tunnel action errors
     } finally {
       setTunnelActions((prev) => ({ ...prev, [tunnelName]: false }));
     }

src/ui/Desktop/Electron Only/ServerConfig.tsx

@@ -43,7 +43,9 @@ export function ServerConfig({
         setServerUrl(config.serverUrl);
         setConnectionStatus("success");
       }
-    } catch (error) {}
+    } catch {
+      // Ignore config loading errors
+    }
   };
 
   const handleTestConnection = async () => {

src/ui/Mobile/Apps/Terminal/TerminalKeyboard.tsx

@@ -110,7 +110,9 @@ export function TerminalKeyboard({
         if (navigator.vibrate) {
           navigator.vibrate(20);
         }
-      } catch (e) {}
+      } catch {
+        // Ignore vibration errors on unsupported devices
+      }
 
       onSendInput(input);
     },