fix KEY_PATH init, compose.yaml sed, registry write, known_hosts dedup, fusermount3 compat

hub/offboard-spoke.sh

@@ -32,7 +32,16 @@ if [ "$(id -u)" -eq 0 ]; then
     die "Run as the hub user, not root."
 fi
 
-check_deps rclone crontab fusermount python3
+check_deps rclone crontab python3
+
+FUSERMOUNT=""
+if command -v fusermount3 >/dev/null 2>&1; then
+    FUSERMOUNT="fusermount3"
+elif command -v fusermount >/dev/null 2>&1; then
+    FUSERMOUNT="fusermount"
+else
+    die "Neither fusermount nor fusermount3 found"
+fi
 
 header "TinyBoard Hub — Offboard Spoke"
 
@@ -64,7 +73,7 @@ read -rp "Are you sure you want to offboard $SPOKE_NAME? [y/N]: " CONFIRM
 
 header "Unmounting Spoke"
 if mountpoint -q "$MOUNT_POINT" 2>/dev/null; then
-    if fusermount -u "$MOUNT_POINT" 2>/dev/null; then
+    if $FUSERMOUNT -u "$MOUNT_POINT" 2>/dev/null; then
         info "Unmounted $MOUNT_POINT."
     else
         warn "Could not unmount $MOUNT_POINT — may already be unmounted."