Phase 5 audit: annotate spec, close HistoryControls partial

Audited every component under clients/web/src/components/ against its
v2_ux_interfaces.md entry. Added an "Audit results" section near the top
of the spec with the verified count (57/62 satisfied, 5 partial) and the
specific gaps still open.

While auditing, closed the HistoryControls gap directly:

- Added RequestMethod union type to core/mcp/types.ts, derived from the
  SDK's Client/Server Request and Notification schemas plus a synthetic
  "response" entry for result/error MessageEntries.
- Typed methodFilter and onMethodFilterChange in HistoryControls,
  HistoryListPanel, historyUtils.extractMethod with RequestMethod.
- Lifted the hardcoded METHOD_OPTIONS list out of HistoryControls into
  a required availableMethods prop. HistoryScreen now derives it from
  the live entries via useMemo + extractMethod.
- Updated HistoryControls.stories.tsx to pass availableMethods.

The remaining 5 partials (ElicitationUrlPanel, InlineElicitationRequest,
InlineSamplingRequest, ExperimentalFeaturesPanel, ResourceListItem) are
either blocked on the v2 core hook layer effort or call out follow-up
work that has its own design questions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/mcp/types.ts

@@ -1,5 +1,7 @@
 import type {
   CallToolResult,
+  ClientNotification,
+  ClientRequest,
   GetPromptResult,
   Implementation,
   JSONRPCErrorResponse,
@@ -10,6 +12,8 @@ import type {
   ReadResourceResult,
   Resource,
   ServerCapabilities,
+  ServerNotification,
+  ServerRequest,
   Tool,
 } from "@modelcontextprotocol/sdk/types.js";
 import type { JsonValue } from "../json/jsonUtils.js";
@@ -98,6 +102,14 @@ export interface MessageEntry {
   duration?: number; // Time between request and response in ms
 }
 
+/** Method name for any MessageEntry traffic, plus synthetic "response" for result/error entries. */
+export type RequestMethod =
+  | ClientRequest["method"]
+  | ClientNotification["method"]
+  | ServerRequest["method"]
+  | ServerNotification["method"]
+  | "response";
+
 export type FetchRequestCategory = "auth" | "transport";
 
 export interface FetchRequestEntry {