fix(shell): avoid shared /tmp shell-init.log

scripts/shell-init.sh

@@ -1,7 +1,17 @@
 # ---- logging ---------------------------------------------------------------
 
 log_shell_init() {
-  printf '%s\n' "shell-init: $*" >>/tmp/shell-init.log 2>/dev/null || true
+  local uid="${UID:-}"
+  [[ -n "$uid" ]] || uid="$(id -u 2>/dev/null || echo unknown)"
+
+  # Avoid a shared logfile in /tmp: if it is ever created root-owned (e.g. from
+  # a root shell), user shells will spam "Permission denied" on every launch.
+  #
+  # Override with:
+  #   export NANUQSAURUS_SHELL_INIT_LOG_FILE=/path/to/log
+  local log_file="${NANUQSAURUS_SHELL_INIT_LOG_FILE:-/tmp/shell-init-${uid}.log}"
+
+  printf '%s\n' "shell-init: $*" >>"$log_file" 2>/dev/null || true
 }
 
 # ---- helpers ---------------------------------------------------------------
@@ -126,4 +136,4 @@ fi
 
 if have bat; then
   alias cat='bat --style=plain --pager=never' 2>/dev/null
-fi
+fi