Add selectable ESP-NOW send path for accel/tap input.

Expose best_effort/fast/wait/reliable via UART, dashboard, and CLI so
loss vs latency can be compared under real multi-pod load.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/cmd_input_send_mode.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+
+	pb "powerpod/gotool/pb"
+)
+
+func runInputSendModeCmd(h hostConn, args []string) error {
+	fs := flag.NewFlagSet("input-send-mode", flag.ExitOnError)
+	write := fs.Bool("set", false, "write mode to slave(s)")
+	mode := fs.Uint("mode", 0, "0=best_effort 1=fast 2=wait 3=reliable")
+	clientID := fs.Uint("client", 0, "slave client_id (required unless -all)")
+	all := fs.Bool("all", false, "apply to every registered slave")
+	_ = fs.Parse(args)
+
+	req := &pb.InputSendModeRequest{
+		Write:      *write,
+		Mode:       pb.InputSendMode(*mode),
+		ClientId:   uint32(*clientID),
+		AllClients: *all,
+	}
+	if *write && !*all && *clientID == 0 {
+		return fmt.Errorf("need -client N or -all when using -set")
+	}
+	if *write && *mode > uint(pb.InputSendMode_INPUT_SEND_RELIABLE) {
+		return fmt.Errorf("mode must be 0..3")
+	}
+
+	r, err := hostInputSendMode(h, req)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("input-send-mode: success=%v mode=%d (%s) client_id=%d slaves_updated=%d\n",
+		r.GetSuccess(), r.GetMode(), inputSendModeName(r.GetMode()), r.GetClientId(),
+		r.GetSlavesUpdated())
+	if *write && !r.GetSuccess() {
+		return fmt.Errorf("input-send-mode rejected")
+	}
+	return nil
+}