feat: package as Claude Code plugin with marketplace distribution

- Add .claude-plugin/plugin.json manifest for direct installation
- Add .claude-plugin/marketplace.json for marketplace distribution
- Reorganize skills to proper skill-name/SKILL.md format
- Update hooks.json with relative paths for portability
- Add new skills: continuous-learning, strategic-compact, eval-harness, verification-loop
- Add new commands: checkpoint, eval, orchestrate, verify
- Update README with plugin installation instructions

Install via:
  /plugin marketplace add affaan-m/everything-claude-code
  /plugin install everything-claude-code@everything-claude-code

.gitignore

@@ -24,3 +24,6 @@ node_modules/
 # Personal configs (if any)
 personal/
 private/
+
+# Session templates (not committed)
+examples/sessions/*.tmp