Enable host OTA over BLE and harden ESP-NOW slave distribution.

Allow the same staged firmware upload path on BLE as UART, fix distribute stack/event-group crashes, and recover sticky slave OTA sessions instead of failing with err=4.

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

goTool/cmd_ota.go

@@ -5,7 +5,7 @@ import (
 	"os"
 )
 
-func runOTA(sp *serialPort, args []string) error {
+func runOTA(t otaTransport, args []string) error {
 	if len(args) < 1 {
 		return fmt.Errorf("usage: ota <firmware.bin>")
 	}
@@ -14,9 +14,17 @@ func runOTA(sp *serialPort, args []string) error {
 		return err
 	}
 
-	sp.mu.Lock()
-	defer sp.mu.Unlock()
-	return runOTAOnPortUnlocked(sp, data, func(p OTAProgress) {
+	switch x := t.(type) {
+	case *serialPort:
+		x.mu.Lock()
+		defer x.mu.Unlock()
+	case *bleLink:
+		if err := x.ensureOTAMTU(); err != nil {
+			return err
+		}
+	}
+
+	return runOTAUnlocked(t, data, func(p OTAProgress) {
 		switch p.Phase {
 		case "preparing", "ready":
 			fmt.Println(p.Message)