Fix release matrix gaps and add background builds

docs/_javascript/firmware_picker.js

@@ -44,7 +44,7 @@
 
   const OTA_LABELS = Object.freeze({
     none: "No LoRa OTA",
-    "lora-receiver": "LoRa OTA enabled / receiver",
+    "lora-receiver": "LoRa OTA repeater",
     "lora-source": "LoRa OTA source only (Full Companion)",
   });
 
@@ -790,7 +790,7 @@
       ],
       zip: [
         "Use the ZIP as the native nRF52 Serial DFU package; it is not an extra archive.",
-        "For LoRa OTA receiving, install the exact-board OTAFIX bootloader first.",
+        "For a LoRa OTA repeater, install the exact-board OTAFIX bootloader first.",
       ],
       uf2: [
         "Place the device in its UF2 bootloader mode and copy the UF2 to the mounted drive.",
@@ -804,7 +804,7 @@
     const extra = [];
     if (profile.ota === "lora-receiver") {
       extra.push(
-        "This installs the LoRa OTA receiver profile. The later update package must still match the exact target and partition signature."
+        "This installs the LoRa OTA repeater profile. The later update package must still match the exact target and partition signature."
       );
     } else if (profile.ota === "lora-source") {
       extra.push(