Add pareset alias for papis cache reset

- Added 'pareset' shell alias that runs 'papis cache reset'
- Placed in the cache management section of shell aliases
- Provides quick access to reset papis database cache

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

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

modules/papis.nix

@@ -56,6 +56,9 @@
 
     # Open documents
     paopen = "papis open";
+    
+    # Cache management
+    pareset = "papis cache reset";
   };
 
   # Shell functions for papis workflow