/**
 * Needle Engine AI skill installer.
 *
 * Auto-detects AI coding agents by checking for their config directories
 * in the project root, then writes the Needle Engine skill in each agent's
 * native format.
 *
 * Supported agents: Claude Code, GitHub Copilot, Cursor, Codex / universal.
 *
 * `.agents/skills/needle-engine/` is always created as the canonical skill
 * location. SKILL.md and downloaded reference files live there. Other agents
 * symlink to it to avoid duplication.
 *
 * Remote reference files (API docs, templates, etc.) linked from SKILL.md are
 * downloaded at install time and stored locally with relative paths.
 *
 * @param {"build" | "serve"} command
 * @param {{} | undefined | null} config
 * @param {import('../types/index.js').userSettings} userSettings
 * @returns {import('vite').Plugin | null}
 */
export function needleAI(command: "build" | "serve", config: {} | undefined | null, userSettings: import("../types/index.js").userSettings): import("vite").Plugin | null;