dlrouter.yaml: register boot-payload and hyperv.zip.xz specialExtensions

The JSON generator emits file_extension values like boe.img.xz,
csot.img.xz, kebab.img.xz and recovery.img.xz (derived from the
boot_<soc>-<board>-<flavor> companion files) and hyperv.zip.xz for
Hyper-V cloud images. For each, REDI_URL gets a matching "-<flavor>"
suffix.

Without these entries in specialExtensions, loadMapJSON never appends
the suffix when building the map key, so the generated redi_url never
resolves and the image 404s through the mirror. Audit in
armbian/armbian.github.io#277 flagged 9 such URLs (xiaomi-elish,
oneplus-kebab, uefi-arm64/x86 hyperv builds).

Refs: #39
Refs: armbian/armbian.github.io#277

Author: SuperKali

dlrouter.yaml

@@ -58,7 +58,15 @@ specialExtensions:
   boot-sms.img.xz: -boot-sms
   boot-boe.img.xz: -boot-boe
   boot-csot.img.xz: -boot-csot
+  # Boot payload companion files (generator emits "<flavor>.img.xz" after stripping
+  # the ".boot_<soc>-<board>-<flavor>" prefix; REDI_URL gets a "-<flavor>" suffix)
+  boe.img.xz: -boe
+  csot.img.xz: -csot
+  kebab.img.xz: -kebab
+  recovery.img.xz: -recovery
   rootfs.img.xz: -rootfs
+  # Hyper-V cloud images
+  hyperv.zip.xz: -hyperv
   img.qcow2: -qcow2
   img.qcow2.xz: -qcow2
   boot.bin.xz: -uboot-bin