Add framework for conceptual docs (#708)

Add framework for conceptual docs plus article on elicitation

Co-authored-by: Stephen Halter <halter73@gmail.com>

docs/concepts/elicitation/samples/server/Elicitation.http

@@ -0,0 +1,58 @@
+@HostAddress = http://localhost:3001
+
+# No session ID, so elicitation capabilities not declared.
+
+POST {{HostAddress}}/
+Accept: application/json, text/event-stream
+Content-Type: application/json
+MCP-Protocol-Version: 2025-06-18
+
+{
+    "jsonrpc": "2.0",
+    "id": 2,
+    "method": "tools/call",
+    "params": {
+        "name": "guess_the_number"
+    }
+}
+
+###
+
+POST {{HostAddress}}/
+Accept: application/json, text/event-stream
+Content-Type: application/json
+
+{
+    "jsonrpc": "2.0",
+    "id": 1,
+    "method": "initialize",
+    "params": {
+        "clientInfo": {
+            "name": "RestClient",
+            "version": "0.1.0"
+        },
+        "capabilities": {
+             "elicitation": {}
+        },
+        "protocolVersion": "2025-06-18"
+    }
+}
+
+###
+
+@SessionId = lgEu87uKTy8kLffZayO5rQ
+
+POST {{HostAddress}}/
+Accept: application/json, text/event-stream
+Content-Type: application/json
+Mcp-Session-Id: {{SessionId}}
+MCP-Protocol-Version: 2025-06-18
+
+{
+    "jsonrpc": "2.0",
+    "id": 2,
+    "method": "tools/call",
+    "params": {
+        "name": "guess_the_number"
+    }
+}