address review: remove .cursor/ duplicate, use is not None checks

Changes based on CodeRabbit review feedback:

1. Remove entire .cursor/ directory — it was an identical copy of the
   main skills/commands/agents/rules, causing maintenance drift.
   Users of Cursor can reference the canonical files directly.

2. Use explicit `is not None` checks instead of truthiness for
   parsed['input'] and parsed['output']. Empty strings or empty
   dicts are valid values that should be preserved.

skills/continuous-learning-v2/hooks/observe.sh

@@ -144,9 +144,9 @@ observation = {
     'session': parsed['session']
 }
 
-if parsed['input']:
+if parsed['input'] is not None:
     observation['input'] = parsed['input']
-if parsed['output']:
+if parsed['output'] is not None:
     observation['output'] = parsed['output']
 
 print(json.dumps(observation))