New channel config (#807)

* Channel config rework

Add staged channel config with tabbed UI, import/export workflow, and global form state refactor

* Improve import dialog config comparison and UI labels

* Review fixes

* Improve state handling

* Fix default filter behaviour

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Co-authored-by: philon- <philon-@users.noreply.github.com>

packages/web/public/i18n/locales/en/channels.json

@@ -3,7 +3,9 @@
     "sectionLabel": "Channels",
     "channelName": "Channel: {{channelName}}",
     "broadcastLabel": "Primary",
-    "channelIndex": "Ch {{index}}"
+    "channelIndex": "Ch {{index}}",
+    "import": "Import",
+    "export": "Export"
   },
   "validation": {
     "pskInvalid": "Please enter a valid {{bits}} bit PSK."