feat: sensitive channel (#11438)

* feat(backend): add isSensitive to Channel

* feat(backend): support isSensitive in channel endpoints

* feat(frontend/channel-editor): support isSensitive in create/edit channel page

* feat(frontend/channel): show sensitive indicator for sensitive channels

* docs(changelog): add チャンネルをセンシティブ指定できるようになりました

* chore: license header for each file

* chore: add isSensitive of channel to Note object

packages/backend/src/models/entities/Channel.ts

@@ -94,4 +94,9 @@ export class Channel {
 		comment: 'The count of users.',
 	})
 	public usersCount: number;
+
+	@Column('boolean', {
+		default: false,
+	})
+	public isSensitive: boolean;
 }