fix(slack): use named import for @slack/bolt App class (#299)

* fix(slack): use named import for @slack/bolt App class

The default import `import bolt from '@slack/bolt'` followed by
`const { App } = bolt` doesn't work correctly in Bun due to ESM/CJS
interop issues. The default export comes through as a function rather
than the module object.

Switching to a named import `import { App } from '@slack/bolt'`
resolves the issue and allows the Slack provider to start successfully.

* fix(slack): align Bolt mock with named App export

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

src/slack/monitor.tool-result.test.ts

@@ -70,7 +70,7 @@ vi.mock("@slack/bolt", () => {
     start = vi.fn().mockResolvedValue(undefined);
     stop = vi.fn().mockResolvedValue(undefined);
   }
-  return { default: { App } };
+  return { App, default: { App } };
 });
 
 const flush = () => new Promise((resolve) => setTimeout(resolve, 0));

src/slack/monitor.ts

@@ -1,8 +1,8 @@
-import type {
-  SlackCommandMiddlewareArgs,
-  SlackEventMiddlewareArgs,
+import {
+  App,
+  type SlackCommandMiddlewareArgs,
+  type SlackEventMiddlewareArgs,
 } from "@slack/bolt";
-import bolt from "@slack/bolt";
 import { chunkText, resolveTextChunkLimit } from "../auto-reply/chunk.js";
 import { hasControlCommand } from "../auto-reply/command-detection.js";
 import { formatAgentEnvelope } from "../auto-reply/envelope.js";
@@ -418,7 +418,6 @@ export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
     return false;
   };
 
-  const { App } = bolt;
   const app = new App({
     token: botToken,
     appToken,