rename: spaghetti-ue5 → unreal-workbench (public name)

Searchable ('unreal' is the marketplace keyword), professional, short (16
chars). 'Spaghetti' stays as the brand layer (description + author fields).
Repo + plugin.json name aligned.

plugin.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://agent-plugins.org/schemas/1.0.0/plugin.schema.json",
-  "name": "spaghetti-ue5",
+  "name": "unreal-workbench",
   "version": "0.1.0",
   "description": "Unreal Engine 5 agent tools — crash analysis, asset auditing, knowledge base, code generation. Powered by Spaghetti Unreal AI Workbench.",
   "author": {
@@ -8,7 +8,7 @@
     "url": "https://spaghetti.gg"
   },
   "homepage": "https://spaghetti.gg",
-  "repository": "https://git.tinirau.com/Tinirau/ue5-agent-plugin",
+  "repository": "https://git.tinirau.com/Tinirau/unreal-workbench",
   "license": "MIT",
   "keywords": ["unreal", "ue5", "spaghetti", "mcp", "game-development", "ai"]
 }