fix(install): preserve temporary worktrees

- stop deleting /tmp wholesale during ZFS pool sizing\n- clean only stale vpsmgr scratch paths and preserve oneclick installs

scripts/10-incus.sh

@@ -155,7 +155,13 @@ elif [[ "$STORAGE" == "zfs" ]]; then
     rm -rf /var/lib/apt/lists/* 2>/dev/null || true
     DEBIAN_FRONTEND=noninteractive apt-get autoremove -y -qq 2>/dev/null || true
     journalctl --vacuum-time=3d >/dev/null 2>&1 || true
-    rm -rf /tmp/* /var/tmp/* 2>/dev/null || true
+    # Never clear /tmp wholesale: oneclick.sh runs from /tmp/vpsmgr-oneclick.*
+    # and deleting the current working directory makes every later child print
+    # "getcwd() failed". Only remove stale scratch paths owned by vpsmgr; the
+    # oneclick worktree is intentionally excluded because it may be active.
+    find /tmp /var/tmp -maxdepth 1 -mindepth 1 -mmin +60 \
+      \( -name 'vpsmgr-traefik.*' -o -name 'vpsmgr-dl.*' -o -name 'vpsmgr-preseed.*' \) \
+      -exec rm -rf -- {} + 2>/dev/null || true
     # Stale kernels: purge ALL linux-image-* except the RUNNING kernel — but
     # if a NEWER kernel than the running one is already installed (upgraded,
     # not yet rebooted), keep that newest one too: deleting it would make the