Add events module with dashboard UI, scheduling, signups, and settings updates; extend env/readme.

src/types/express-session.d.ts

@@ -0,0 +1,13 @@
+import 'express-session';
+
+declare module 'express-session' {
+  interface SessionData {
+    user?: any;
+    guilds?: any[];
+    token?: {
+      access_token: string;
+      refresh_token?: string;
+      expires_at?: number;
+    };
+  }
+}