feat(bulk): mode, submode and RST are repair fields, so allow them

They were excluded as "per-QSO", alongside callsign and date. That rule confused
two different things: bulk edit is not for describing QSOs, it is for REPAIRING
a batch of them — an import that mapped every contact to SSB, an ADIF that
carried no MODE at all. Refusing because a hundred rows should not normally
share a value left the operator editing a hundred rows by hand.

Setting the mode CLEARS the submode. A submode belongs to the mode it was
recorded under; left behind it contradicts the new one, and "FT8 with a submode
of USB" is not a thing — worse, the submode is what most ADIF readers believe.

Band is still refused on its own, and that half of the rule stands. It travels
with the frequency through BulkSetFrequency, which writes the pair: a band
contradicting its own frequency is invalid ADIF, and every export would carry
the contradiction out into the world. Callsign and date stay out too — they
identify the contact rather than describe it.

changelog.json

@@ -2,8 +2,12 @@
   {
     "version": "0.24.6",
     "date": "",
-    "en": [],
-    "fr": []
+    "en": [
+      "Bulk edit can now set mode, submode and RST. They were excluded as per-QSO fields, which missed the point: bulk edit is for repairing a batch — an import that mapped every contact to SSB, an ADIF with no mode at all — and refusing meant editing a hundred rows one at a time. Setting the mode clears the submode, since one left over from the old mode contradicts the new one. Band stays with frequency, which already sets the two together."
+    ],
+    "fr": [
+      "L édition groupée sait enfin régler le mode, le sous-mode et le RST. Ils étaient exclus comme champs propres à chaque QSO, ce qui manquait l essentiel : l édition groupée sert à RÉPARER un lot — un import qui a tout mis en SSB, un ADIF sans aucun mode — et refuser obligeait à corriger cent lignes une par une. Régler le mode efface le sous-mode, celui de l ancien mode contredisant le nouveau. La bande reste avec la fréquence, qui pose déjà les deux ensemble."
+    ]
   },
   {
     "version": "0.24.5",