fix: say why playing a recording on the air did nothing

"I click play and nothing happens" is what an operator sees when a function
returns an error into a promise the interface swallows. Every refusal in the
playback path is now logged as well as returned, and each names its own cause —
audio not initialised, the take still running, the take empty, the device
rejecting the file.

One of those was not even checked: playing back needs an OUTPUT device INTO the
radio, which is a different setting from the recorder's input and is very likely
unset on a station that has only ever recorded. It now refuses with that
sentence instead of failing somewhere inside the player.

changelog.json

@@ -4,11 +4,13 @@
     "date": "",
     "en": [
       "FlexRadio: in split, OpsLog stays on the receive slice instead of following the transmitter.",
-      "QSO recording works on CW again. Your own sidetone is not in the file, the other station is."
+      "QSO recording works on CW again. Your own sidetone is not in the file, the other station is.",
+      "Playing a recording on the air now says why when it cannot — most often no audio output to the radio is configured."
     ],
     "fr": [
       "FlexRadio : en split, OpsLog reste sur la slice de réception au lieu de suivre l'émission.",
-      "L'enregistrement des QSO fonctionne à nouveau en CW. Votre propre signal d'écoute n'est pas dans le fichier, celui du correspondant l'est."
+      "L'enregistrement des QSO fonctionne à nouveau en CW. Votre propre signal d'écoute n'est pas dans le fichier, celui du correspondant l'est.",
+      "L'émission d'un enregistrement indique désormais pourquoi elle échoue — le plus souvent aucune sortie audio vers la radio n'est configurée."
     ]
   },
   {