Add 3 Claude Code skills to Agent Skills section

[manja316]

Adds three practical Claude Code skills to the Agent Skills section:

1. session-continuity — Anti-amnesia skill that checkpoints working state to survive context compaction and session restarts
2. dependency-auditor — Multi-ecosystem security auditor with noise filtering (classifies findings into critical/dev-only/transitive/disputed tiers)
3. project-init-wizard — Auto-detects tech stack and generates optimized CLAUDE.md with conventions, recommended skills, and settings

All three are MIT licensed with real SKILL.md files and source code on GitHub.