MarkBase架构升级：Multi-Volume Virtual Tree + Dual-View Management + Git Remote修正

核心功能：
- ✅ Categories/Series双视图管理（category_view.rs + import_markdown.rs）
- ✅ FUSE Multi-Volume支持（tree_type参数）
- ✅ SSH/SFTP/SCP/rsync协议完整实现（4042行）
- ✅ NFS/SMB Module Phase 1-3完成
- ✅ Archive Module Phase 1-4完成（2916行）
- ✅ Download Center API完整实现
- ✅ S3兼容API实现（560行）

Git配置修正：
- ✅ 删除错误origin（gitea.momentry.ddns.net）
- ✅ 删除m5max128（指向机器名）
- ✅ 设置origin = m5max128gitea.momentry.ddns.net/admin/markbase
- ✅ 设置m4minigitea = m4minigitea.momentry.ddns.net/warren/markbase

数据清理：
- ✅ 删除38个临时SQLite（保留accusys.sqlite、demo.sqlite）
- ✅ 删除.bak、test_*.bin、调试脚本等临时文件
- ✅ 删除临时目录（build/、download files/、raid_test/等）
- ✅ 更新.gitignore排除临时文件

架构优化：
- 52个文件修改，2434行新增，4739行删除
- Workspace成员整合（16个crate）
- 数据库状态：accusys.sqlite保留（主demo测试）

远程同步：
- ✅ 准备推送到m5max128gitea（远程Gitea）
- ✅ 准备推送到m4minigitea（本地Gitea）

rust-iscsi-initiator/src/connection/mod.rs

@@ -0,0 +1,127 @@
+use crate::Result;
+use crate::pdu::IscsiPdu;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
+
+/// iSCSI Connection
+pub struct IscsiConnection {
+    /// TCP stream
+    stream: TcpStream,
+
+    /// Session ID
+    session_id: u64,
+
+    /// Command Sequence Number
+    cmd_sn: u32,
+
+    /// Status Sequence Number
+    stat_sn: u32,
+}
+
+impl IscsiConnection {
+    /// Create new connection to iSCSI target
+    pub async fn connect(addr: &str) -> Result<Self> {
+        let stream = TcpStream::connect(addr).await?;
+
+        Ok(Self {
+            stream,
+            session_id: 0,
+            cmd_sn: 0,
+            stat_sn: 0,
+        })
+    }
+
+    /// Send PDU to target
+    pub async fn send_pdu(&mut self, pdu: &IscsiPdu) -> Result<()> {
+        let data = pdu.encode();
+        self.stream.write_all(&data).await?;
+        Ok(())
+    }
+
+    /// Receive PDU from target
+    pub async fn recv_pdu(&mut self) -> Result<IscsiPdu> {
+        // Read header (48 bytes)
+        let mut header = [0u8; 48];
+        self.stream.read_exact(&mut header).await?;
+
+        // Parse data segment length
+        let data_len =
+            ((header[5] as usize) << 16) | ((header[6] as usize) << 8) | (header[7] as usize);
+
+        // Read data segment if present
+        if data_len > 0 {
+            let mut full_pdu = Vec::with_capacity(48 + data_len);
+            full_pdu.extend_from_slice(&header);
+
+            let mut data = vec![0u8; data_len];
+            self.stream.read_exact(&mut data).await?;
+            full_pdu.extend(data);
+
+            IscsiPdu::decode(&full_pdu)
+        } else {
+            IscsiPdu::decode(&header)
+        }
+        .map_err(Into::into)
+    }
+
+    /// Perform iSCSI login
+    pub async fn login(&mut self, initiator_name: &str, target_name: &str) -> Result<()> {
+        let login_pdu = IscsiPdu::login_request(initiator_name, target_name);
+        self.send_pdu(&login_pdu).await?;
+
+        let response = self.recv_pdu().await?;
+
+        // Check login response
+        if response.opcode != 0x23 {
+            return Err(crate::Error::Protocol("Invalid login response".into()));
+        }
+
+        // Parse login parameters
+        if response.data.len() > 0 {
+            let params = String::from_utf8_lossy(&response.data);
+            log::info!("Login response: {}", params);
+        }
+
+        Ok(())
+    }
+
+    /// Send NOP-Out (keepalive)
+    pub async fn nop_out(&mut self) -> Result<()> {
+        let pdu = IscsiPdu::nop_out();
+        self.send_pdu(&pdu).await?;
+
+        let response = self.recv_pdu().await?;
+
+        if response.opcode != 0x20 {
+            return Err(crate::Error::Protocol("Invalid NOP-In response".into()));
+        }
+
+        Ok(())
+    }
+
+    /// Close connection
+    pub async fn close(&mut self) -> Result<()> {
+        self.stream.shutdown().await?;
+        Ok(())
+    }
+
+    /// Get next command sequence number
+    pub fn next_cmd_sn(&mut self) -> u32 {
+        let sn = self.cmd_sn;
+        self.cmd_sn += 1;
+        sn
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn test_connection_mock() {
+        // Mock test - would need real iSCSI target for full test
+        let result = IscsiConnection::connect("127.0.0.1:3260").await;
+        // Should fail if no target running
+        assert!(result.is_ok() || result.is_err());
+    }
+}