Group third-party MCP plugins under third_party/

Moves gong/ and salesforce/ to third_party/ and points their marketplace
`source` paths at the new location. Nested source paths resolve fine:
resolvePluginSourcePath treats source as a relative path and only strips a
leading ./

Co-authored-by: Cursor <cursoragent@cursor.com>

.cursor-plugin/marketplace.json

@@ -90,12 +90,12 @@
     },
     {
       "name": "gong",
-      "source": "gong",
+      "source": "third_party/gong",
       "description": "Gong MCP integration for revenue intelligence — account summaries, deal insights, and call briefs."
     },
     {
       "name": "salesforce",
-      "source": "salesforce",
+      "source": "third_party/salesforce",
       "description": "Connect Cursor to Salesforce via Salesforce Hosted MCP — query, search, create, update, and traverse records in your org."
     }
   ]

README.md

@@ -20,8 +20,8 @@ Official Cursor plugins for popular developer tools, frameworks, and SaaS produc
 | `gmail` | [Gmail](gmail/) | Cursor | Productivity | Connect Cursor to Gmail via Google's remote MCP server — search, read, draft, label, and manage email. |
 | `google-drive` | [Google Drive](google-drive/) | Cursor | Productivity | Connect Cursor to Google Drive via Google's remote MCP server — search, read, create, share, and manage files. |
 | `google-calendar` | [Google Calendar](google-calendar/) | Cursor | Productivity | Connect Cursor to Google Calendar via Google's remote MCP server — list calendars, search events, and create or update meetings. |
-| `gong` | [Gong](gong/) | Cursor | Integrations | Gong MCP integration for revenue intelligence — account summaries, deal insights, and call briefs. |
-| `salesforce` | [Salesforce](salesforce/) | Cursor | Integrations | Connect Cursor to Salesforce via Salesforce Hosted MCP — query, search, create, update, and traverse records in your org. |
+| `gong` | [Gong](third_party/gong/) | Cursor | Integrations | Gong MCP integration for revenue intelligence — account summaries, deal insights, and call briefs. |
+| `salesforce` | [Salesforce](third_party/salesforce/) | Cursor | Integrations | Connect Cursor to Salesforce via Salesforce Hosted MCP — query, search, create, update, and traverse records in your org. |
 
 Author values match each plugin’s `plugin.json` `author.name` (Cursor lists `plugins@cursor.com` in the manifest).