foundkey-js: use file extensions in imports

Technically, ESM modules require imports to include file extensions.

For whatever reason this didn't seem to be required when importing into
the client, but it does seem to be required for use in the backend.

packages/foundkey-js/src/api.ts

@@ -1,4 +1,4 @@
-import { Endpoints } from './api.types';
+import { Endpoints } from './api.types.js';
 
 const MK_API_ERROR = Symbol();
 

packages/foundkey-js/src/api.types.ts

@@ -3,7 +3,7 @@ import {
 	LiteInstanceMetadata,
 	MeDetailed,
 	Note, NoteFavorite, OriginType, Page, ServerInfo, Stats, User, UserDetailed, UserGroup, UserList, UserSorting, Notification, NoteReaction, Signin, MessagingMessage,
-} from './entities';
+} from './entities.js';
 
 type TODO = Record<string, any> | null;
 

packages/foundkey-js/src/index.ts

@@ -1,8 +1,8 @@
-import { Endpoints } from './api.types';
-import Stream, { Connection } from './streaming';
-import { Channels } from './streaming.types';
-import { Acct } from './acct';
-import * as consts from './consts';
+import { Endpoints } from './api.types.js';
+import Stream, { Connection } from './streaming.js';
+import { Channels } from './streaming.types.js';
+import { Acct } from './acct.js';
+import * as consts from './consts.js';
 
 export {
 	Endpoints,

packages/foundkey-js/src/streaming.ts

@@ -1,7 +1,7 @@
 import autobind from 'autobind-decorator';
 import { EventEmitter } from 'eventemitter3';
 import ReconnectingWebsocket from 'reconnecting-websocket';
-import { BroadcastEvents, Channels } from './streaming.types';
+import { BroadcastEvents, Channels } from './streaming.types.js';
 
 export function urlQuery(obj: Record<string, string | number | boolean | undefined>): string {
 	const params = Object.entries(obj)

packages/foundkey-js/src/streaming.types.ts

@@ -1,4 +1,4 @@
-import { Antenna, CustomEmoji, DriveFile, MeDetailed, MessagingMessage, Note, Notification, PageEvent, User, UserGroup } from './entities';
+import { Antenna, CustomEmoji, DriveFile, MeDetailed, MessagingMessage, Note, Notification, PageEvent, User, UserGroup } from './entities.js';
 
 type FIXME = any;