fix(kernel): Handle unreadable module files in selftest.sh

Improve error handling in module discovery by identifying unreadable
`.ko` files and providing detailed error messages. Suggest actions like
unzip or rebuild to resolve issues.

kernel/selftest.sh

@@ -107,8 +107,14 @@ if [ -z "$KO" ]; then
 		[ -d "$dir" ] || continue
 		for cand in "$dir"/${MODULE}*.ko; do
 			[ -f "$cand" ] || continue
-			vm="$(modinfo -F vermagic "$cand" 2>/dev/null)"
+			if vm="$(modinfo -F vermagic "$cand" 2>/dev/null)" && [ -n "$vm" ]; then
-			msg="$msg"$'\n'"       $cand (built for ${vm%% *})"
+				note="built for ${vm%% *}"
+			else
+				# modinfo couldn't read it - usually not an ELF .ko at all
+				# (e.g. a still-zipped release file). Show what it really is.
+				note="UNREADABLE: $(file -b "$cand" 2>/dev/null || echo 'not a kernel module') - unzip/rebuild?"
+			fi
+			msg="$msg"$'\n'"       $cand ($note)"
 			any=1
 		done
 	done