refactor: Remove hooks - SessionEnd/PreCompact not useful for notifications

Hooks execute after Claude Code exits, so output is not visible.
Removed: setup command, install-hooks.sh, hooks.json, session-end-reminder.sh
Bump version to 2.2.0

🤖 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": "2.1.4",
+  "version": "2.2.0",
   "author": {
     "name": "Romfast Team"
   }