perf: install env checks

script/install.d/00-os.sh

@@ -5,14 +5,16 @@
 #   Print operating system information and hint which installer path will run.
 #
 
-if [[ "$OSTYPE" == "darwin"* ]]; then
+log_info "Environment: DOTS_OS=$DOTS_OS, DOTS_PKG=$DOTS_PKG, DOTS_ENV=$DOTS_ENV"
+
+if [[ "$DOTS_OS" == "macos" ]]; then
     # macOS info
     sw_vers
     log_info "Detected macOS (OSTYPE=$OSTYPE)"
     log_info "Package manager: Homebrew (brew)"
     log_info "Code path: macOS-only brew scripts will run; Linux package scripts are skipped."
 
-elif [[ "$OSTYPE" == "linux-gnu"* ]]; then
+elif [[ "$DOTS_OS" == "linux" ]]; then
     # Linux info
     if [[ -r /etc/os-release ]]; then
         cat /etc/os-release
@@ -21,17 +23,16 @@ elif [[ "$OSTYPE" == "linux-gnu"* ]]; then
     fi
 
     log_info "Detected Linux (OSTYPE=$OSTYPE, ID=${ID:-unknown}, ID_LIKE=${ID_LIKE:-n/a}, NAME=${NAME:-n/a}, VERSION_ID=${VERSION_ID:-n/a})"
+    log_info "Package manager detected: ${DOTS_PKG:-none}"
 
-    if command -v apt-get >/dev/null 2>&1; then
-        log_info "Package manager detected: apt-get"
-        export DOTS_PKG_MGR=apt
-    elif command -v pacman >/dev/null 2>&1; then
-        log_info "Package manager detected: pacman"
-        export DOTS_PKG_MGR=pacman
-    else
-        log_warn "No known package manager (apt-get/pacman) found on Linux."
+    if [[ -z "$DOTS_PKG" ]]; then
+        log_warn "No known package manager (apt-get/pacman/dnf) found on Linux."
     fi
 
 else
     log_error "Unknown OS: $OSTYPE"
 fi
+
+if [[ "$DOTS_ENV" == "codespaces" ]]; then
+    log_info "Running in GitHub Codespaces"
+fi