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>

plugins/ralph-wiggum/hooks/hooks.json

@@ -0,0 +1,15 @@
+{
+  "description": "Ralph Wiggum plugin stop hook for self-referential loops",
+  "hooks": {
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh"
+          }
+        ]
+      }
+    ]
+  }
+}