Tighten conformance gates with HasMatchingDraftWireVersion guard

The previous gates activated draft-only scenarios as soon as the conformance
package version reached 0.2.0. That works for conformance >= 0.2.0-alpha.3 (or a
local build of main) where the bundled DRAFT_PROTOCOL_VERSION constant matches
this SDK's value, but breaks under 0.2.0-alpha.2 because alpha.2 still ships the
placeholder 'DRAFT-2026-v1' wire string while this SDK only accepts the
ratified '2026-07-28'.

Add HasMatchingDraftWireVersion() that greps the bundled
node_modules/@modelcontextprotocol/conformance/dist/index.js for this SDK's
McpHttpHeaders.DraftProtocolVersion (the bundle is minified so we can't grep
the constant name, but the literal version string survives bundling and is
specific enough to be reliable). AND it into the three gates:
HasSep2243Scenarios(), HasCachingScenario(), HasMrtrScenarios().

Also unify HasMrtrScenarios() with HasSep2243Scenarios()/HasCachingScenario():
read the installed version from node_modules instead of the pinned version
from package.json. This lets a local 'npm install --no-save <path-to-conformance>'
activate MRTR scenarios the same way it already activates SEP-2243/caching.

Under 0.2.0-alpha.2 (this PR's pin), the 14 gated draft scenarios all SKIP
cleanly instead of failing on wire-string mismatch. Once 0.2.0-alpha.3 publishes
(or a local main build is installed), the gates auto-activate.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: halter73

tests/Common/Utils/NodeHelpers.cs

@@ -2,6 +2,7 @@
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Text.RegularExpressions;
+using ModelContextProtocol.Protocol;
 
 namespace ModelContextProtocol.Tests.Utils;
 
@@ -187,8 +188,12 @@ public static bool IsNodeInstalled()
     /// the pinned version in package.json) means this also returns <see langword="true"/>
     /// when a newer private build has been installed locally via
     /// <c>npm install --no-save &lt;path-to-conformance&gt;</c>.
+    /// Additionally requires that the installed conformance package emits the draft wire
+    /// version this SDK speaks — see <see cref="HasMatchingDraftWireVersion"/>.
     /// </summary>
-    public static bool HasSep2243Scenarios() => HasInstalledConformanceVersionAtLeast(new Version(0, 2, 0));
+    public static bool HasSep2243Scenarios()
+        => HasInstalledConformanceVersionAtLeast(new Version(0, 2, 0))
+        && HasMatchingDraftWireVersion();
 
     /// <summary>
     /// Checks whether the SEP-2549 "caching" conformance scenario (added in conformance
@@ -197,8 +202,47 @@ public static bool IsNodeInstalled()
     /// Reading the installed version (rather than the pinned version in package.json) means
     /// this also returns <see langword="true"/> when a newer private build has been installed
     /// locally via <c>npm install --no-save &lt;path-to-conformance&gt;</c>.
+    /// Additionally requires that the installed conformance package emits the draft wire
+    /// version this SDK speaks — see <see cref="HasMatchingDraftWireVersion"/>.
     /// </summary>
-    public static bool HasCachingScenario() => HasInstalledConformanceVersionAtLeast(new Version(0, 2, 0));
+    public static bool HasCachingScenario()
+        => HasInstalledConformanceVersionAtLeast(new Version(0, 2, 0))
+        && HasMatchingDraftWireVersion();
+
+    /// <summary>
+    /// Returns <see langword="true"/> when the installed conformance package's bundled
+    /// dist emits the same draft protocol version string as this SDK
+    /// (<see cref="McpHttpHeaders.DraftProtocolVersion"/>). Used to suppress draft-only
+    /// conformance scenarios when the published conformance binary is still pinned to a
+    /// stale wire string (for example, conformance 0.2.0-alpha.2 ships
+    /// <c>"DRAFT-2026-v1"</c> while this SDK speaks <c>"2026-07-28"</c>).
+    /// </summary>
+    /// <remarks>
+    /// This check is a pragmatic alternative to inspecting the conformance package's
+    /// internal constants: the bundled <c>dist/index.js</c> is minified so we can't grep
+    /// the constant name, but the literal version string survives bundling and is unique
+    /// enough to be a reliable signal.
+    /// </remarks>
+    public static bool HasMatchingDraftWireVersion()
+    {
+        try
+        {
+            var repoRoot = FindRepoRoot();
+            var distPath = Path.Combine(
+                repoRoot, "node_modules", "@modelcontextprotocol", "conformance", "dist", "index.js");
+            if (!File.Exists(distPath))
+            {
+                return false;
+            }
+
+            var bundled = File.ReadAllText(distPath);
+            return bundled.Contains(McpHttpHeaders.DraftProtocolVersion, StringComparison.Ordinal);
+        }
+        catch
+        {
+            return false;
+        }
+    }
 
     /// <summary>
     /// Returns <see langword="true"/> when the conformance package installed in node_modules
@@ -373,42 +417,20 @@ private static bool ConformanceOutputIndicatesSuccess(string output)
     }
 
     /// <summary>
-    /// Checks whether the SEP-2322 (Multi Round-Trip Requests / IncompleteResult)
-    /// conformance scenarios are available by reading the conformance package version
-    /// from the repo's package.json. MRTR scenarios require a conformance package version
-    /// that includes SEP-2322 support (see
+    /// Checks whether the SEP-2322 (Multi Round-Trip Requests / InputRequiredResult)
+    /// conformance scenarios are available, by reading the <em>installed</em> conformance
+    /// package version from node_modules. The <c>incomplete-result-*</c> scenarios were
+    /// introduced in conformance package 0.2.0 (see
     /// https://github.com/modelcontextprotocol/conformance/pull/188).
+    /// Reading the installed version (rather than the pinned version in package.json) means
+    /// this also returns <see langword="true"/> when a newer private build has been installed
+    /// locally via <c>npm install --no-save &lt;path-to-conformance&gt;</c>.
+    /// Additionally requires that the installed conformance package emits the draft wire
+    /// version this SDK speaks — see <see cref="HasMatchingDraftWireVersion"/>.
     /// </summary>
     public static bool HasMrtrScenarios()
-    {
-        try
-        {
-            var repoRoot = FindRepoRoot();
-            var packageJsonPath = Path.Combine(repoRoot, "package.json");
-            if (!File.Exists(packageJsonPath))
-            {
-                return false;
-            }
-
-            var json = System.Text.Json.JsonDocument.Parse(File.ReadAllText(packageJsonPath));
-            if (json.RootElement.TryGetProperty("dependencies", out var deps) &&
-                deps.TryGetProperty("@modelcontextprotocol/conformance", out var versionElement))
-            {
-                var versionStr = versionElement.GetString();
-                if (versionStr is not null && Version.TryParse(versionStr, out var version))
-                {
-                    // SEP-2322 scenarios are expected in conformance package >= 0.2.0
-                    return version >= new Version(0, 2, 0);
-                }
-            }
-
-            return false;
-        }
-        catch
-        {
-            return false;
-        }
-    }
+        => HasInstalledConformanceVersionAtLeast(new Version(0, 2, 0))
+        && HasMatchingDraftWireVersion();
 
     private static ProcessStartInfo NpmStartInfo(string arguments, string workingDirectory)
     {