feat: Add /learn:setup command for hook installation

- Add setup.md command to install SessionEnd and PreCompact hooks
- Add install-hooks.sh script for automatic hook installation to ~/.claude/settings.json
- Hooks remind user to run /learn:analyze before session end or auto-compact
- Bump version to 2.1.2

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/learn/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "learn",
   "description": "Claude Learn: Session analysis for patterns and gotchas with domain-based memory, selective saving, and memory hygiene",
-  "version": "2.1.1",
+  "version": "2.1.2",
   "author": {
     "name": "Romfast Team"
   }