feat: implement cmd management for targets, LUNs, and TPGTs (fixes #36)

- Fix target delete URL path mismatch (/targets/ -> /target/)
- Implement target create/delete server handlers with proper validation
- Add DeleteTarget method with force flag and mutex locking to SCSITargetService
- Implement full LU management: create/list/delete through CLI, client, and server
- Add TPGT list command to show target portal group tags
- Add unit tests for target/LU router handlers and SCSI service

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pkg/api/options.go

@@ -29,3 +29,36 @@ type TargetListOptions struct {
 	Name    string
 	Verbose bool
 }
+
+type LuCreateRequest struct {
+	TargetName string `json:"targetName"`
+	DeviceID   uint64 `json:"deviceID"`
+	LUN        uint64 `json:"lun"`
+	Path       string `json:"path"`
+	BlockShift uint   `json:"blockShift"`
+}
+
+type LuListOptions struct {
+	TargetName string
+}
+
+type LuRemoveOptions struct {
+	TargetName string `json:"targetName"`
+	LUN        uint64 `json:"lun"`
+}
+
+type LuInfo struct {
+	LUN    uint64 `json:"lun"`
+	Path   string `json:"path"`
+	Online bool   `json:"online"`
+	Size   uint64 `json:"size"`
+}
+
+type TpgtListOptions struct {
+	TargetName string
+}
+
+type TpgtInfo struct {
+	TPGT    uint16   `json:"tpgt"`
+	Portals []string `json:"portals"`
+}