feat: Add ralph-wiggum plugin for iterative self-referential development

Migrates the ralph-wiggum plugin from internal marketplace to public marketplace.
Implements Geoffrey Huntley's "Ralph Wiggum" technique using Claude Code's Stop
hook mechanism for continuous iterative development loops.

Key features:
- Interactive self-referential AI loops in current session
- Stop hook intercepts exit and feeds same prompt back
- Iteration tracking and completion promise detection
- Max iterations safety limits

Changes:
- Remove all tmux dependencies and background execution mode
- Simplify to interactive-only mode using Stop hooks
- Add comprehensive error handling with clear messages
- Fix documentation to accurately describe Stop hook mechanism
- Add input validation for all command-line arguments
- Register plugin in public marketplace

Security fixes:
- Remove eval usage (command injection vulnerability)
- Add numeric validation before arithmetic operations
- Remove silent error suppression

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

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

.claude-plugin/marketplace.json

@@ -101,6 +101,17 @@
       },
       "source": "./plugins/frontend-design",
       "category": "development"
+    },
+    {
+      "name": "ralph-wiggum",
+      "description": "Interactive self-referential AI loops for iterative development. Claude works on the same task repeatedly, seeing its previous work, until completion.",
+      "version": "1.0.0",
+      "author": {
+        "name": "Daisy Hollman",
+        "email": "daisy@anthropic.com"
+      },
+      "source": "./plugins/ralph-wiggum",
+      "category": "development"
     }
   ]
 }