chore: SOTA audit fixes – catalog recursive, readme regex, docs, CI, installer

- P0: Catalog includes nested skills (listSkillIdsRecursive), 626 skills
- P0: update_readme.py regex fixes 'high-performance agentic skills'
- P1: SKILL_ANATOMY risk values aligned to none|safe|critical|offensive (EN + vi)
- P1: requirements.txt + CONTRIBUTING Python setup
- P1: data/package.json version 4.6.0
- P2: npm run test + CI test step; validator docs + validation-baseline in .gitignore
- P3: Installer --version/--tag support; CI npm audit; __pycache__ in .gitignore

bin/install.js

@@ -16,11 +16,15 @@ function resolveDir(p) {
 function parseArgs() {
   const a = process.argv.slice(2);
   let pathArg = null;
+  let versionArg = null;
+  let tagArg = null;
   let cursor = false, claude = false, gemini = false, codex = false;
 
   for (let i = 0; i < a.length; i++) {
     if (a[i] === '--help' || a[i] === '-h') return { help: true };
     if (a[i] === '--path' && a[i + 1]) { pathArg = a[++i]; continue; }
+    if (a[i] === '--version' && a[i + 1]) { versionArg = a[++i]; continue; }
+    if (a[i] === '--tag' && a[i + 1]) { tagArg = a[++i]; continue; }
     if (a[i] === '--cursor') { cursor = true; continue; }
     if (a[i] === '--claude') { claude = true; continue; }
     if (a[i] === '--gemini') { gemini = true; continue; }
@@ -28,7 +32,7 @@ function parseArgs() {
     if (a[i] === 'install') continue;
   }
 
-  return { pathArg, cursor, claude, gemini, codex };
+  return { pathArg, versionArg, tagArg, cursor, claude, gemini, codex };
 }
 
 function defaultDir(opts) {
@@ -58,11 +62,13 @@ Options:
   --gemini    Install to ~/.gemini/skills (Gemini CLI)
   --codex     Install to ~/.codex/skills (Codex CLI)
   --path <dir> Install to <dir> (default: ~/.agent/skills)
+  --version <ver>  After clone, checkout tag v<ver> (e.g. 4.6.0 -> v4.6.0)
+  --tag <tag>      After clone, checkout this tag (e.g. v4.6.0)
 
 Examples:
   npx antigravity-awesome-skills
   npx antigravity-awesome-skills --cursor
-  npx antigravity-awesome-skills --codex
+  npx antigravity-awesome-skills --version 4.6.0
   npx antigravity-awesome-skills --path ./my-skills
 `);
 }
@@ -114,6 +120,13 @@ function main() {
     run('git', ['clone', REPO, target]);
   }
 
+  const ref = tagArg || (versionArg ? (versionArg.startsWith('v') ? versionArg : `v${versionArg}`) : null);
+  if (ref) {
+    console.log(`Checking out ${ref}…`);
+    process.chdir(target);
+    run('git', ['checkout', ref]);
+  }
+
   console.log(`\nInstalled to ${target}`);
   console.log('Pick a bundle in docs/BUNDLES.md and use @skill-name in your AI assistant.');
 }