feat(scripts): add install-apt-packages.sh for Debian/Ubuntu

Install essential developer packages via apt:
- Build tools: build-essential, cmake, pkg-config, autoconf, automake, libtool
- Dev libraries: libssl-dev, libffi-dev, zlib1g-dev, libreadline-dev, etc.
- CLI utilities: jq, tmux, tree, unzip, shellcheck, socat, gnupg

Curated to avoid duplicates with cargo/go installs (ripgrep, fd, fzf, etc.).
Uses batched apt install for efficiency, exits gracefully on non-Debian systems.

scripts/install-apt-packages.sh

@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+set -euo pipefail
+# @description Install essential apt packages for development.
+#
+# shellcheck source=shared.sh
+source "$DOTFILES/config/shared.sh"
+
+msgr run "Starting to install apt packages"
+
+if ! command -v apt &> /dev/null; then
+  msgr warn "apt not found (not a Debian-based system)"
+  exit 0
+fi
+
+packages=(
+  # Build essentials
+  build-essential    # gcc, g++, make
+  cmake              # Cross-platform build system
+  pkg-config         # Helper for compiling against libraries
+  autoconf           # Automatic configure script builder
+  automake           # Makefile generator
+  libtool            # Generic library support script
+
+  # Libraries for compiling languages
+  libssl-dev         # SSL development headers
+  libffi-dev         # Foreign function interface
+  zlib1g-dev         # Compression library
+  libreadline-dev    # Command-line editing
+  libbz2-dev         # Bzip2 compression
+  libsqlite3-dev     # SQLite database
+  libncurses-dev     # Terminal UI library
+
+  # CLI utilities (not in cargo/go/npm)
+  jq                 # JSON processor
+  tmux               # Terminal multiplexer
+  tree               # Directory listing
+  unzip              # Archive extraction
+  shellcheck         # Shell script linter
+  socat              # Multipurpose network relay
+  gnupg              # GPG encryption/signing
+  software-properties-common  # add-apt-repository command
+)
+
+install_packages()
+{
+  local to_install=()
+
+  for pkg in "${packages[@]}"; do
+    pkg="${pkg%%#*}"
+    pkg="${pkg// /}"
+    [[ -z "$pkg" ]] && continue
+
+    if dpkg -s "$pkg" &> /dev/null; then
+      msgr ok "$pkg already installed"
+    else
+      to_install+=("$pkg")
+    fi
+  done
+
+  if [[ ${#to_install[@]} -gt 0 ]]; then
+    msgr run "Installing ${#to_install[@]} packages: ${to_install[*]}"
+    sudo apt update
+    sudo apt install -y "${to_install[@]}"
+  else
+    msgr ok "All packages already installed"
+  fi
+}
+
+main()
+{
+  install_packages
+  msgr yay "apt package installations complete"
+}
+
+main "$@"