fix: add noninteractive install script mode

scripts/install/install.ps1

@@ -27,6 +27,10 @@ function Prompt-YesNo {
         [string]$Prompt
     )
 
+    if ($env:CODEX_INSTALL_SCRIPT_NONINTERACTIVE -eq "true") {
+        return $false
+    }
+
     if ([Console]::IsInputRedirected -or [Console]::IsOutputRedirected) {
         return $false
     }

scripts/install/install.sh

@@ -60,6 +60,9 @@ parse_args() {
       --help | -h)
         cat <<EOF
 Usage: install.sh [--release VERSION]
+
+Environment:
+  CODEX_INSTALL_SCRIPT_NONINTERACTIVE=true  Skip prompts and use default answers.
 EOF
         exit 0
         ;;
@@ -488,6 +491,10 @@ classify_existing_codex() {
 prompt_yes_no() {
   prompt="$1"
 
+  if [ "${CODEX_INSTALL_SCRIPT_NONINTERACTIVE:-}" = "true" ]; then
+    return 1
+  fi
+
   if ( : </dev/tty ) 2>/dev/null; then
     printf '%s [y/N] ' "$prompt" >/dev/tty
     if ! IFS= read -r answer </dev/tty; then