fix: load eventsource with import() for the SSE relay

server.js became an ES module in the ESM migration, but the SSE_RELAY
code path still used require('eventsource'). Setting SSE_RELAY, as the
README recommends for local development, made the bot fail to start
with ERR_AMBIGUOUS_MODULE_SYNTAX (require() is not available in ESM).

Load it with a dynamic import() instead, which keeps eventsource an
optional dev-only dependency, and use its named EventSource export since
eventsource v3+ no longer provides a default export.

Fixes: #706
Signed-off-by: NopeCharon <115794254+NopeCharon@users.noreply.github.com>

Author: NopeCharon

server.js

@@ -22,7 +22,7 @@ app.listen(port, () => {
 // may open up an SSE relay channel helpful for local debugging
 // of github repository events, wo/having to deploy changes
 if (process.env.SSE_RELAY) {
-  const EventSource = require('eventsource')
+  const { EventSource } = await import('eventsource')
   const es = new EventSource(process.env.SSE_RELAY)
   es.onmessage = (e) => {
     try {