fix: address Copilot review round 2 on #2318

- fetchTracking: media types and HTTP methods compare case-insensitively;
  a `Request` input's own method is honoured; the SSE line scanner
  accepts LF, CRLF and a bare CR, holding a trailing CR until the next
  chunk decides whether it is half of a CRLF.
- MessageTrackingTransport does not report a send failure for a request
  the caller aborted through `requestSignal`, and InspectorClient keeps a
  request whose send failed with a request timeout — both are sent,
  unanswered requests, which is the state to keep reporting.
- createTransportNode builds a fetch tracker when any tracking callback
  is supplied, not only `onFetchRequest`.
- RemoteClientTransport's relay wait expires with the SDK's own timeout
  shape, so the web client's relay timeout is annotated like every other.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01APKSYHGxXBUpnR7ErFiLJn
Signed-off-by: cliffhall <cliff@futurescale.com>

core/mcp/node/transport.ts

@@ -55,6 +55,12 @@ export function createTransportNode(
     interceptAuthChallenges = false,
     onAuthChallengeObserved,
   } = options;
+  // Any of the three tracking callbacks earns a tracker: each is optional on
+  // the tracker itself, and a caller that wants only stream updates (or only
+  // bodies) must not be silently handed the bare fetch (#2318).
+  const wantsFetchTracking = Boolean(
+    onFetchRequest || onFetchResponseBody || onFetchStreamUpdate,
+  );
 
   // `optionsFetchFn` is the caller's whole fetch stack and already sits on top of
   // a proxy-aware base when one is needed — the Node clients install
@@ -115,7 +121,7 @@ export function createTransportNode(
     const sseFetch = configuredSseFetch
       ? withChallengeObserver(configuredSseFetch)
       : fetchWithOptionalAuthIntercept;
-    const trackedFetch = onFetchRequest
+    const trackedFetch = wantsFetchTracking
       ? createFetchTracker(sseFetch, {
           trackRequest: onFetchRequest,
           updateResponseBody: onFetchResponseBody,
@@ -136,7 +142,7 @@ export function createTransportNode(
       ...(headers && { headers }),
     };
 
-    const postFetch = onFetchRequest
+    const postFetch = wantsFetchTracking
       ? createFetchTracker(fetchWithOptionalAuthIntercept, {
           trackRequest: onFetchRequest,
           updateResponseBody: onFetchResponseBody,
@@ -164,7 +170,7 @@ export function createTransportNode(
       ...(headers && { headers }),
     };
 
-    const transportFetch = onFetchRequest
+    const transportFetch = wantsFetchTracking
       ? createFetchTracker(fetchWithOptionalAuthIntercept, {
           trackRequest: onFetchRequest,
           updateResponseBody: onFetchResponseBody,