Add docs for server-level auth (#583)

* Add 'Secure Your MCP Server with OAuth' page

* Disambiguation

* Update 'Securing Arcade MCP' page

* Add inline youtube video

* Update docs to reflect recent changes to implementation

* Address comments

Author: EricGustin

app/en/home/build-tools/_meta.tsx

@@ -7,5 +7,7 @@ export default {
   "providing-useful-tool-errors": "Providing useful tool errors",
   "retry-tools-with-improved-prompt": "Retry tools with improved prompt",
   "call-tools-from-mcp-clients": "Call tools from MCP clients",
+  "secure-your-mcp-server": "Secure Your MCP Server with OAuth",
+  "server-level-vs-tool-level-auth": "Server-Level vs Tool-Level Authorization",
   "migrate-from-toolkits": "Migrate from toolkits",
 };