Advertise the Docker docs MCP server

Publish an MCP Server Card at /.well-known/mcp/server-card.json
pointing at https://mcp-docs.docker.com/mcp, so agents doing MCP
discovery can find the official Docker docs endpoint. Mirror the
serverInfo and capabilities reported by the server's initialize
response.

Also add a one-line pointer near the top of llms.txt so LLMs fetching
the index learn about the structured-access alternative.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

layouts/home.llms.txt

@@ -3,6 +3,8 @@
 {{- $grouped := $sorted.GroupBy "Section" -}}
 
 # Docker Documentation
+
+> MCP endpoint for structured agent access: https://mcp-docs.docker.com/mcp
 {{- range $grouped }}
 
 ## {{ humanize .Key }}

static/.well-known/mcp/server-card.json

@@ -0,0 +1,23 @@
+{
+  "serverInfo": {
+    "name": "llms-txt",
+    "version": "1.26.0",
+    "description": "Official Docker documentation MCP server. Exposes a fetch_docker_docs tool that returns the docs.docker.com content index."
+  },
+  "transport": {
+    "type": "http",
+    "url": "https://mcp-docs.docker.com/mcp"
+  },
+  "capabilities": {
+    "prompts": {
+      "listChanged": false
+    },
+    "resources": {
+      "subscribe": false,
+      "listChanged": false
+    },
+    "tools": {
+      "listChanged": false
+    }
+  }
+}