fix: add hooks declaration to plugin.json for proper hook loading

Previously hooks were not loaded when the plugin was installed because
plugin.json didn't declare the hooks path. This caused errors like:
"Stop hook error: .../skills/continuous-learning/evaluate-session.sh: No such file"

The hooks are defined in hooks/hooks.json and use JS implementations in
scripts/hooks/ directory.

.claude-plugin/plugin.json

@@ -23,5 +23,6 @@
     "best-practices"
   ],
   "commands": "./commands",
-  "skills": "./skills"
+  "skills": "./skills",
+  "hooks": "./hooks/hooks.json"
 }