feat: add fluxer upstream source and self-hosting documentation

- Clone of github.com/fluxerapp/fluxer (official upstream)
- SELF_HOSTING.md: full VM rebuild procedure, architecture overview,
  service reference, step-by-step setup, troubleshooting, seattle reference
- dev/.env.example: all env vars with secrets redacted and generation instructions
- dev/livekit.yaml: LiveKit config template with placeholder keys
- fluxer-seattle/: existing seattle deployment setup scripts

fluxer/packages/api/src/infrastructure/ILiveKitService.tsx

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import type {ChannelID, GuildID, UserID} from '@fluxer/api/src/BrandedTypes';
+import type {VoiceRegionMetadata, VoiceServerRecord} from '@fluxer/api/src/voice/VoiceModel';
+
+interface CreateTokenParams {
+	userId: UserID;
+	guildId?: GuildID;
+	channelId: ChannelID;
+	connectionId: string;
+	tokenNonce: string;
+	regionId: string;
+	serverId: string;
+	mute?: boolean;
+	deaf?: boolean;
+	canSpeak?: boolean;
+	canStream?: boolean;
+	canVideo?: boolean;
+}
+
+interface UpdateParticipantParams {
+	userId: UserID;
+	guildId?: GuildID;
+	channelId: ChannelID;
+	connectionId: string;
+	regionId: string;
+	serverId: string;
+	mute?: boolean;
+	deaf?: boolean;
+}
+
+interface UpdateParticipantPermissionsParams {
+	userId: UserID;
+	guildId?: GuildID;
+	channelId: ChannelID;
+	connectionId: string;
+	regionId: string;
+	serverId: string;
+	canSpeak: boolean;
+	canStream: boolean;
+	canVideo: boolean;
+}
+
+interface DisconnectParticipantParams {
+	userId: UserID;
+	guildId?: GuildID;
+	channelId: ChannelID;
+	connectionId: string;
+	regionId: string;
+	serverId: string;
+}
+
+interface ListParticipantsParams {
+	guildId?: GuildID;
+	channelId: ChannelID;
+	regionId: string;
+	serverId: string;
+}
+
+export interface ListParticipantsSuccess {
+	status: 'ok';
+	participants: Array<{identity: string}>;
+}
+
+export interface ListParticipantsError {
+	status: 'error';
+	errorCode: string;
+	retryable: boolean;
+}
+
+export type ListParticipantsResult = ListParticipantsSuccess | ListParticipantsError;
+
+export abstract class ILiveKitService {
+	abstract createToken(params: CreateTokenParams): Promise<{token: string; endpoint: string}>;
+	abstract updateParticipant(params: UpdateParticipantParams): Promise<void>;
+	abstract updateParticipantPermissions(params: UpdateParticipantPermissionsParams): Promise<void>;
+	abstract disconnectParticipant(params: DisconnectParticipantParams): Promise<void>;
+	abstract listParticipants(params: ListParticipantsParams): Promise<ListParticipantsResult>;
+	abstract getDefaultRegionId(): string | null;
+	abstract getRegionMetadata(): Array<VoiceRegionMetadata>;
+	abstract getServer(regionId: string, serverId: string): VoiceServerRecord | null;
+}