docs(resources): link "resource templates" to MCP spec

Author: tony

docs/reference/api/resources.md

@@ -4,10 +4,12 @@
 
 MCP resources are addressable documents the server exposes at
 ``tmux://`` URIs. Clients read them via ``resources/read``. All
-libtmux-mcp resources are **resource templates** — each URI includes
-a ``{?socket_name}`` query parameter for socket isolation, plus
-structural path parameters (``{session_name}``, ``{pane_id}``, …) so
-a single template covers every session, window, or pane.
+libtmux-mcp resources are
+[resource templates](https://modelcontextprotocol.io/specification/2025-11-25/server/resources#resource-templates)
+— each URI includes a ``{?socket_name}`` query parameter for socket
+isolation, plus structural path parameters (``{session_name}``,
+``{pane_id}``, …) so a single template covers every session, window,
+or pane.
 
 Every resource delivers a snapshot of the tmux hierarchy at call
 time. Agents use them for read-only inspection; any write workflow