fix brew uninstall fallback consistency

lib/uninstall/brew.sh

@@ -35,6 +35,21 @@ is_homebrew_available() {
     command -v brew > /dev/null 2>&1
 }
 
+# Check whether a cask is still recorded as installed in Homebrew.
+# Exit codes:
+#   0 - cask is installed
+#   1 - cask is not installed
+#   2 - install state could not be determined
+is_brew_cask_installed() {
+    local cask_name="$1"
+    [[ -n "$cask_name" ]] || return 2
+    is_homebrew_available || return 2
+
+    local cask_list
+    cask_list=$(HOMEBREW_NO_ENV_HINTS=1 brew list --cask 2> /dev/null) || return 2
+    grep -qxF "$cask_name" <<< "$cask_list"
+}
+
 # Extract cask token from a Caskroom path
 # Args: $1 - path (must be inside Caskroom)
 # Prints: cask token to stdout
@@ -211,7 +226,12 @@ brew_uninstall_cask() {
 
     # Verify removal (only if not timed out)
     local cask_gone=true app_gone=true
-    HOMEBREW_NO_ENV_HINTS=1 brew list --cask 2> /dev/null | grep -qxF "$cask_name" && cask_gone=false
+    if is_brew_cask_installed "$cask_name"; then
+        cask_gone=false
+    else
+        local cask_state=$?
+        [[ $cask_state -eq 1 ]] || cask_gone=false
+    fi
     [[ -n "$app_path" && -e "$app_path" ]] && app_gone=false
 
     # Success: uninstall worked and both are gone, or already uninstalled