Rename plugin from "ralph-wiggum" to "ralph-loop"

Update all internal references to use "Ralph Loop" as the prominent name
Keep explanatory text noting it "implements the Ralph Wiggum technique"
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

plugins/ralph-loop/hooks/hooks.json

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