fix(everything): implement graceful HTTP elicitation degradation

Implement graceful degradation for elicitation on HTTP transport:
- STDIO: Full elicitation works via sendRequest
- HTTP: Catches elicitation failure, uses default interpretation
- Task completes successfully on both transports

simulate-research-query now uses try-catch around sendRequest and
includes explanatory message when elicitation is skipped on HTTP.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/everything/transports/streamableHttp.ts

@@ -1,10 +1,37 @@
-import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
-import { InMemoryEventStore } from "@modelcontextprotocol/sdk/examples/shared/inMemoryEventStore.js";
+import { StreamableHTTPServerTransport, EventStore } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
 import express, { Request, Response } from "express";
 import { createServer } from "../server/index.js";
 import { randomUUID } from "node:crypto";
 import cors from "cors";
 
+// Simple in-memory event store for SSE resumability
+class InMemoryEventStore implements EventStore {
+  private events: Map<string, { streamId: string; message: unknown }> = new Map();
+
+  async storeEvent(streamId: string, message: unknown): Promise<string> {
+    const eventId = randomUUID();
+    this.events.set(eventId, { streamId, message });
+    return eventId;
+  }
+
+  async replayEventsAfter(
+    lastEventId: string,
+    { send }: { send: (eventId: string, message: unknown) => Promise<void> }
+  ): Promise<string> {
+    const entries = Array.from(this.events.entries());
+    const startIndex = entries.findIndex(([id]) => id === lastEventId);
+    if (startIndex === -1) return lastEventId;
+
+    let lastId: string = lastEventId;
+    for (let i = startIndex + 1; i < entries.length; i++) {
+      const [eventId, { message }] = entries[i];
+      await send(eventId, message);
+      lastId = eventId;
+    }
+    return lastId;
+  }
+}
+
 console.log("Starting Streamable HTTP server...");
 
 // Express app with permissive CORS for testing with Inspector direct connect mode