Add rules/perl/ with 5 rule files (coding-style, testing, patterns,
hooks, security) following the same structure as existing languages.
Update README.md, README.zh-CN.md, and rules/README.md to document
Perl support including badges, directory trees, install instructions,
and rule counts.
When installed as a plugin, /plan triggers Claude Code's built-in plan
mode instead of the plugin's plan skill. Updated all 4 README files
(EN, zh-CN, zh-TW, ja-JP) to show the plugin-namespaced form with a
comment noting the shorter form works for manual installs.
Also fixes markdownlint MD012 violation in chief-of-staff.md (trailing
double blank line from #280 merge).
Fixes#297
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)
New community skills: content-hash-cache-pattern, cost-aware-llm-pipeline,
regex-vs-llm-structured-text, swift-actor-persistence, swift-protocol-di-testing
