Rename ralph-wiggum plugin to ralph-loop per legal guidance (#142)

- Rename plugin from "ralph-wiggum" to "ralph-loop" to avoid trademark concerns
- Update all internal references to use "Ralph Loop" as the prominent name
- Keep explanatory text noting it "implements the Ralph Wiggum technique" (allowed)
- Rename plugin directory from plugins/ralph-wiggum to plugins/ralph-loop
- Update marketplace.json with new plugin name and source path
- Update plugin-dev documentation references

This change follows legal's recommendation to replace "Wiggum" with "Loop"
in the plugin name while still explaining the technique origin.

Slack thread: https://anthropic.slack.com/archives/C09KU300P7F/p1767741142753959

Co-authored-by: Claude <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -328,15 +328,15 @@
       "homepage": "https://github.com/anthropics/claude-plugins-public/tree/main/plugins/frontend-design"
     },
     {
-      "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.",
+      "name": "ralph-loop",
+      "description": "Interactive self-referential AI loops for iterative development, implementing the Ralph Wiggum technique. Claude works on the same task repeatedly, seeing its previous work, until completion.",
       "author": {
         "name": "Anthropic",
         "email": "support@anthropic.com"
       },
-      "source": "./plugins/ralph-wiggum",
+      "source": "./plugins/ralph-loop",
       "category": "development",
-      "homepage": "https://github.com/anthropics/claude-plugins-public/tree/main/plugins/ralph-wiggum"
+      "homepage": "https://github.com/anthropics/claude-plugins-public/tree/main/plugins/ralph-loop"
     },
     {
       "name": "hookify",