fix: Preserve only keys/role across sysupgrade, not version/profile

/etc/parahub/ wildcard was preserving old version and profile files
across OTA updates, preventing firmware version from being updated.
Now only keys and role are preserved — version, profile, and port_map
come fresh from new firmware.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

files/etc/sysupgrade.conf

@@ -1,3 +1,4 @@
-/etc/parahub/
+/etc/parahub/keys
+/etc/parahub/role
 /etc/yggdrasil.conf
 /etc/dropbear/