feat: Add core utility functions for terminal output

lib/output.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# =============================================================================
+# lib/output.sh
+# Terminal output helpers: colors, log levels, and step banners.
+# =============================================================================
+
+if [[ -t 1 ]]; then
+  GREEN='\033[0;32m'
+  YELLOW='\033[1;33m'
+  CYAN='\033[0;36m'
+  RED='\033[0;31m'
+  BOLD='\033[1m'
+  NC='\033[0m'
+else
+  GREEN='' YELLOW='' CYAN='' RED='' BOLD='' NC=''
+fi
+
+info()    { echo -e "${CYAN}[INFO]${NC}    $*"; }
+success() { echo -e "${GREEN}[OK]${NC}      $*"; }
+warn()    { echo -e "${YELLOW}[WARN]${NC}    $*"; }
+error()   { echo -e "${RED}[ERROR]${NC}   $*" >&2; }
+step()    { echo -e "\n${BOLD}${YELLOW}━━━ $* ━━━${NC}"; }
+
+box() {
+  local max_len=0
+  for line in "$@"; do
+    [[ ${#line} -gt $max_len ]] && max_len=${#line}
+  done
+  local border
+  border=$(printf '─%.0s' $(seq 1 $((max_len + 2))))
+  echo -e "${CYAN}┌${border}┐${NC}"
+  for line in "$@"; do
+    printf "${CYAN}│${NC} %-${max_len}s ${CYAN}│${NC}\n" "$line"
+  done
+  echo -e "${CYAN}└${border}┘${NC}"
+}