feat: add security guides and sanitize external links across repo

New articles:
- the-security-guide.md: "The Shorthand Guide to Securing Your Agent" (595 lines)
  Attack vectors, sandboxing, sanitization, OWASP Top 10, observability
- the-openclaw-guide.md: "The Hidden Danger of OpenClaw" (470 lines)
  Security analysis of OpenClaw, MiniClaw thesis, industry evidence

External link sanitization (22 files across EN, zh-CN, zh-TW, ja-JP, .cursor):
- Removed third-party GitHub links from skills and guides
- Replaced with inline descriptions to prevent transitive prompt injection
- Kept official org links (Anthropic, Google, Supabase, Mixedbread)

README.md

@@ -69,6 +69,15 @@ This repo is the raw code only. The guides explain everything.
 
 ## What's New
 
+### v1.6.0 — Codex CLI, AgentShield & Marketplace (Feb 2026)
+
+- **Codex CLI support** — New `/codex-setup` command generates `codex.md` for OpenAI Codex CLI compatibility
+- **7 new skills** — `search-first`, `swift-actor-persistence`, `swift-protocol-di-testing`, `regex-vs-llm-structured-text`, `content-hash-cache-pattern`, `cost-aware-llm-pipeline`, `skill-stocktake`
+- **AgentShield integration** — `/security-scan` skill runs AgentShield directly from Claude Code; 1282 tests, 102 rules
+- **GitHub Marketplace** — ECC Tools GitHub App live at [github.com/marketplace/ecc-tools](https://github.com/marketplace/ecc-tools) with free/pro/enterprise tiers
+- **30+ community PRs merged** — Contributions from 30 contributors across 6 languages
+- **978 internal tests** — Expanded validation suite across agents, skills, commands, hooks, and rules
+
 ### v1.4.1 — Bug Fix (Feb 2026)
 
 - **Fixed instinct import content loss** — `parse_instinct_file()` was silently dropping all content after frontmatter (Action, Evidence, Examples sections) during `/instinct-import`. Fixed by community contributor @ericcai0814 ([#148](https://github.com/affaan-m/everything-claude-code/issues/148), [#161](https://github.com/affaan-m/everything-claude-code/pull/161))
@@ -387,7 +396,7 @@ Both options create:
 
 ### AgentShield — Security Auditor
 
-> Built at the Claude Code Hackathon (Cerebral Valley x Anthropic, Feb 2026). 912 tests, 98% coverage, 102 static analysis rules.
+> Built at the Claude Code Hackathon (Cerebral Valley x Anthropic, Feb 2026). 1282 tests, 98% coverage, 102 static analysis rules.
 
 Scan your Claude Code configuration for vulnerabilities, misconfigurations, and injection risks.
 
@@ -1027,7 +1036,7 @@ This project is free and open source. Sponsors help keep it maintained and growi
 - **Longform Guide (Advanced):** [The Longform Guide to Everything Claude Code](https://x.com/affaanmustafa/status/2014040193557471352)
 - **Follow:** [@affaanmustafa](https://x.com/affaanmustafa)
 - **zenith.chat:** [zenith.chat](https://zenith.chat)
-- **Skills Directory:** [awesome-agent-skills](https://github.com/JackyST0/awesome-agent-skills)
+- **Skills Directory:** awesome-agent-skills (community-maintained directory of agent skills)
 
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