feat: initial open-source project structure

Agent Skill for searching and downloading torrents via TorrentClaw.
Includes SKILL.md with OpenClaw metadata, bash scripts for torrent
client detection, CONTRIBUTING.md, CHANGELOG.md, CI/CD with GitHub
Actions (shellcheck + conventional commits), lefthook git hooks,
Makefile, and .editorconfig.

scripts/detect-client.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# Detects installed torrent clients and outputs JSON.
+# Usage: ./detect-client.sh
+
+set -euo pipefail
+
+# --- OS Detection ---
+os_name=$(uname -s)
+distro="unknown"
+
+case "$os_name" in
+  Linux)
+    if [ -f /etc/os-release ]; then
+      # shellcheck source=/dev/null
+      distro=$(. /etc/os-release && echo "${ID:-unknown}")
+    fi
+    ;;
+  Darwin)
+    distro="macos"
+    ;;
+  MINGW*|MSYS*|CYGWIN*)
+    os_name="Windows"
+    distro="windows"
+    ;;
+esac
+
+# --- Client Detection ---
+
+# Transmission
+transmission_path=$(command -v transmission-remote 2>/dev/null || true)
+transmission_installed="false"
+transmission_daemon="false"
+if [ -n "$transmission_path" ]; then
+  transmission_installed="true"
+  if transmission-remote -l >/dev/null 2>&1; then
+    transmission_daemon="true"
+  fi
+fi
+
+# aria2
+aria2_path=$(command -v aria2c 2>/dev/null || true)
+aria2_installed="false"
+aria2_daemon="false"
+if [ -n "$aria2_path" ]; then
+  aria2_installed="true"
+  if curl -sf http://localhost:6800/jsonrpc -d '{"jsonrpc":"2.0","id":"test","method":"aria2.getVersion"}' >/dev/null 2>&1; then
+    aria2_daemon="true"
+  fi
+fi
+
+# --- Preferred Client ---
+preferred="none"
+if [ "$transmission_installed" = "true" ]; then
+  preferred="transmission"
+elif [ "$aria2_installed" = "true" ]; then
+  preferred="aria2"
+fi
+
+# --- JSON Output ---
+cat <<EOF
+{
+  "os": "$os_name",
+  "distro": "$distro",
+  "clients": {
+    "transmission": {
+      "installed": $transmission_installed,
+      "path": $([ -n "$transmission_path" ] && echo "\"$transmission_path\"" || echo "null"),
+      "daemonRunning": $transmission_daemon
+    },
+    "aria2": {
+      "installed": $aria2_installed,
+      "path": $([ -n "$aria2_path" ] && echo "\"$aria2_path\"" || echo "null"),
+      "daemonRunning": $aria2_daemon
+    }
+  },
+  "preferred": "$preferred"
+}
+EOF