[WIP] Refactor everything server to be more modular and use recommended APIs.

Adding Trigger Elicitation Request and Get Roots List tools

* Updated architecture.md

* Added roots.ts
  - tracks roots by sessionId
  - setRootsListChangedHandler
    - listens for roots changed notification from the client
      - updates the roots map by sessionId
      - sends log notification or error to the client

* In server/index.ts
  - import setRootsListChangedHandler
  - in clientConnected callback
    - call setRootsListChangedHandler passing server and sessionId

* In sse.ts, stdio.ts, and streamableHttp.ts
  - receive clientConnected from server factory
  - call clientConnected when server is connected to transport
* Added get-roots-list.ts
  - registerGetRootsListTool
    - Registers the 'get-roots-list' tool with the given MCP server.

* Added trigger-elicitation-request.ts
  - registerTriggerElicitationRequestTool
    - registered tool sends an elicitation request that exercises all supported field types

* In tools/index.ts
  - imports registerTriggerElicitationRequestTool and registerGetRootsListTool
  - in registerTools
    - call registerTriggerElicitationRequestTool and registerGetRootsListTool, passing server

src/everything/transports/streamableHttp.ts

@@ -35,7 +35,7 @@ app.post("/mcp", async (req: Request, res: Response) => {
       // Reuse existing transport
       transport = transports.get(sessionId)!;
     } else if (!sessionId) {
-      const { server, cleanup } = createServer();
+      const { server, clientConnected, cleanup } = createServer();
 
       // New initialization request
       const eventStore = new InMemoryEventStore();
@@ -47,6 +47,7 @@ app.post("/mcp", async (req: Request, res: Response) => {
           // This avoids race conditions where requests might come in before the session is stored
           console.log(`Session initialized with ID: ${sessionId}`);
           transports.set(sessionId, transport);
+          clientConnected(sessionId);
         },
       });