Register Penpot's MCP server, whose token rides in the URL

Penpot's MCP server reads the user key only from the userToken query
parameter, never a header. link-mcp now substitutes a {TOKEN} placeholder
in a server's URL instead of sending the Authorization header, and the
servers list gains a penpot row that uses it.

user/agents/mcp/servers

@@ -6,7 +6,8 @@
 # git. This file carries no secret, so it is tracked like the rest of user/ and
 # a new machine gets the same servers by dropping its own env file beside it.
 #
-# A row with no token variable registers without an Authorization header.
+# A row with no token variable registers without an Authorization header. A URL
+# containing {TOKEN} gets the token substituted there instead of as a header.
 #
 # Lines beginning with # are comments and blank lines are ignored.
 
@@ -23,3 +24,8 @@ bill-tracker    http  https://mcp.billtracker.gbrown.org/mcp
 # Atlassian's hosted MCP server for Jira and Confluence. No token: it is an
 # OAuth server and Claude Code signs in through /mcp on first use.
 atlassian       http  https://mcp.atlassian.com/v1/mcp
+
+# Penpot's MCP server on the VPS (penpot.gbrown.org). The key is a per-user MCP
+# key from Penpot's Account > Integrations, and Penpot only reads it from the
+# query string, hence {TOKEN}. The same key connects the in-file MCP plugin.
+penpot          http  https://penpot.gbrown.org/mcp/stream?userToken={TOKEN}  PENPOT_MCP_TOKEN