Address PR #1236 review feedback

- Rename RequestMethod → MessageMethod. The type covers notifications and
  results, not just requests; the new name matches the JSDoc.
- Normalize imports to the @inspector/core/mcp/types.js path alias in
  HistoryListPanel, historyUtils, and HistoryScreen (HistoryControls was
  already using the alias).
- Document the cast invariant in extractMethod: SDK types message.method
  as string, but every MessageEntry in this app originates from SDK
  schemas, so the narrowing is safe.
- Type SAMPLE_METHODS as MessageMethod[] in HistoryControls stories so
  the literal-type narrowing isn't lost across the spread.

Skipped two reviewer suggestions: the Mantine Select inline cast (reviewer
self-resolved) and the stale-methodFilter-on-clear UX edge case (deferred
as a separate follow-up — not a Phase 5 audit gap).

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

clients/web/src/components/groups/historyUtils.ts

@@ -1,11 +1,10 @@
-import type {
-  MessageEntry,
-  RequestMethod,
-} from "../../../../../core/mcp/types.js";
+import type { MessageEntry, MessageMethod } from "@inspector/core/mcp/types.js";
 
-export function extractMethod(entry: MessageEntry): RequestMethod {
+export function extractMethod(entry: MessageEntry): MessageMethod {
   if ("method" in entry.message) {
-    return entry.message.method as RequestMethod;
+    // Cast: SDK types message.method as `string`, but every entry in this
+    // app's MessageEntry log originates from MCP SDK schemas.
+    return entry.message.method as MessageMethod;
   }
   return "response";
 }