feat: Management of multiple slices on Flexradio

internal/cat/cat.go

@@ -245,9 +245,24 @@ func (m *Manager) SendSpot(s SpotInfo) {
 // FlexTXState is the FlexRadio transmit/ATU state surfaced to the dedicated
 // FlexRadio control tab. Levels are 0-100. (Phase 1: controls + state pushed by
 // the radio over TCP; live meters arrive over a separate UDP stream later.)
+// FlexSliceInfo identifies one FlexRadio receiver slice (A/B/C/D…) for the
+// panel, so the operator sees every slice and which one is active/TX.
+type FlexSliceInfo struct {
+	Index  int    `json:"index"`  // 0-based slice index
+	Letter string `json:"letter"` // A, B, C, D…
+	FreqHz int64  `json:"freq_hz"`
+	Mode   string `json:"mode,omitempty"` // ADIF mode
+	Band   string `json:"band,omitempty"`
+	Active bool   `json:"active"` // the focused/operating slice
+	TX     bool   `json:"tx"`     // this slice transmits
+}
+
 type FlexTXState struct {
 	Available    bool   `json:"available"` // backend is Flex and handshaked
 	Model        string `json:"model,omitempty"`
+	// Slices lists every in-use receiver slice (A/B/C/D…) so the panel can show
+	// them all and highlight the active one. The active slice drives everything.
+	Slices []FlexSliceInfo `json:"slices,omitempty"`
 	RFPower      int    `json:"rf_power"`
 	TunePower    int    `json:"tune_power"`
 	Tune         bool   `json:"tune"`         // tune carrier active
@@ -339,6 +354,8 @@ type FlexController interface {
 	SetMute(bool) error
 	SetRXAntenna(string) error
 	SetTXAntenna(string) error
+	SetActiveSlice(int) error // focus slice idx so commands target it
+	SetTXSlice(int) error     // make slice idx the transmitter (tx=1)
 	SetSplit(bool) error
 	SetNB(bool) error
 	SetNBLevel(int) error