feat: migrate logs API from REST to IPC streaming (#4277)

* feat: migrate logs API from REST to IPC streaming

- Replace REST API `/logs` calls with IPC streaming implementation
- Add new `src-tauri/src/ipc/logs.rs` with `LogsMonitor` for real-time log streaming
- Implement duplicate stream prevention with level tracking
- Add frontend-backend communication via Tauri commands for log management
- Remove WebSocket compatibility, maintain IPC-only mode
- Fix duplicate monitoring task startup when toggling log service
- Add proper task lifecycle management with JoinHandle cleanup

* refactor: remove dead code from logs.rs to fix clippy warnings

- Remove unused `timestamp` field from LogItem struct
- Remove unused `client` field from LogsMonitor struct
- Remove unused methods: `is_fresh`, `get_current_monitoring_level`, `get_current_logs`
- Simplify LogsMonitor initialization by removing client dependency
- All clippy warnings with -D warnings now resolved

* refactor: extract duplicate fmt_bytes function to utils module

- Create new utils/format.rs module with fmt_bytes function
- Remove duplicate fmt_bytes implementations from traffic.rs and memory.rs
- Update imports to use shared utils::format::fmt_bytes
- Add comprehensive unit tests for fmt_bytes function
- Ensure DRY principle compliance and code maintainability

src-tauri/src/ipc/general.rs

@@ -382,29 +382,5 @@ impl IpcManager {
         }
     }
 
-    // 流量数据相关
-    #[allow(dead_code)]
-    pub async fn get_traffic(&self) -> AnyResult<serde_json::Value> {
-        let url = "/traffic";
-        logging!(info, Type::Ipc, true, "IPC: 发送 GET 请求到 {}", url);
-        let result = self.send_request("GET", url, None).await;
-        logging!(
-            info,
-            Type::Ipc,
-            true,
-            "IPC: /traffic 请求结果: {:?}",
-            result
-        );
-        result
-    }
-
-    // 内存相关
-    #[allow(dead_code)]
-    pub async fn get_memory(&self) -> AnyResult<serde_json::Value> {
-        let url = "/memory";
-        logging!(info, Type::Ipc, true, "IPC: 发送 GET 请求到 {}", url);
-        let result = self.send_request("GET", url, None).await;
-        logging!(info, Type::Ipc, true, "IPC: /memory 请求结果: {:?}", result);
-        result
-    }
+    // 日志相关功能已迁移到 logs.rs 模块，使用流式处理
 }