fix(bandopen): the moon is not a band opening

A 2 m opening was announced at 9650 km towards Japan. The callsigns gave it
away — 7M4RRM, JA7RPC, JF1AWC — all working EME, which is routine on 2 m and
reported to PSK Reporter like anything else. Real contacts, real grids, and no
evidence whatsoever about the band: an operator turning a beam on that bearing
would hear nothing.

Removing the flat 2400 km ceiling was right; it threw away genuine multi-hop Es
on 6 m. "No limit anywhere" was the overcorrection. The limit is per band now,
and it is physics rather than a threshold: 2 m reaches a few thousand kilometres
by tropospheric duct or a chain of Es clouds and no further, so 3500 km, and
4 m 4000. Six and ten metres keep no ceiling — multi-hop Es and F2 genuinely do
go round the world, which is the case that started all this.

Pinned from both sides: the 9650 km Japanese burst produces nothing, and a
2000 km 2 m burst in one sector still counts.

changelog.json

@@ -3,10 +3,12 @@
     "version": "0.24.7",
     "date": "",
     "en": [
-      "QSOs logged from WSJT-X now carry the space weather and the distance, like hand-logged ones. The UDP path stamped the station profile, the DXCC and the QSL defaults but not SFI, A, K or distance — so an operator running digital had those fields empty across the whole log. Space weather is only stamped on a contact less than a day old: a logger re-broadcasting its backlog would otherwise be handed this morning readings for last month contacts."
+      "QSOs logged from WSJT-X now carry the space weather and the distance, like hand-logged ones. The UDP path stamped the station profile, the DXCC and the QSL defaults but not SFI, A, K or distance — so an operator running digital had those fields empty across the whole log. Space weather is only stamped on a contact less than a day old: a logger re-broadcasting its backlog would otherwise be handed this morning readings for last month contacts.",
+      "Band openings: EME contacts are no longer mistaken for an opening. A 2 m opening was announced at 9650 km towards Japan on stations working moonbounce — real contacts, but the moon says nothing about the band, and an antenna pointed that way finds nothing. Each band now has the longest path the atmosphere can actually carry: 3500 km on 2 m, 4000 on 4 m, and no limit at all on 6 and 10 m where multi-hop really does go round the world."
     ],
     "fr": [
-      "Les QSO enregistrés depuis WSJT-X portent désormais la météo spatiale et la distance, comme ceux saisis à la main. Le chemin UDP posait le profil station, le DXCC et les défauts QSL mais ni SFI, ni A, ni K, ni distance — un opérateur en numérique avait donc ces champs vides sur tout son log. La météo spatiale n est posée que sur un contact de moins d un jour : sinon un logiciel qui rediffuse son historique se verrait attribuer les relevés de ce matin sur des contacts du mois dernier."
+      "Les QSO enregistrés depuis WSJT-X portent désormais la météo spatiale et la distance, comme ceux saisis à la main. Le chemin UDP posait le profil station, le DXCC et les défauts QSL mais ni SFI, ni A, ni K, ni distance — un opérateur en numérique avait donc ces champs vides sur tout son log. La météo spatiale n est posée que sur un contact de moins d un jour : sinon un logiciel qui rediffuse son historique se verrait attribuer les relevés de ce matin sur des contacts du mois dernier.",
+      "Ouvertures de bande : les contacts EME ne sont plus pris pour une ouverture. Une ouverture 2 m était annoncée à 9650 km vers le Japon sur des stations en rebond lunaire — de vrais contacts, mais la Lune ne dit rien de la bande, et une antenne pointée par là ne trouve rien. Chaque bande a désormais la distance maximale que l atmosphère peut réellement porter : 3500 km en 2 m, 4000 en 4 m, et aucune limite en 6 et 10 m où les sauts multiples font vraiment le tour du monde."
     ]
   },
   {