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/marketing/src/components/icons/ChatsIcon.tsx

@@ -0,0 +1,33 @@
+/*
+ * 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/>.
+ */
+
+/** @jsxRuntime automatic */
+/** @jsxImportSource hono/jsx */
+
+interface ChatsIconProps {
+	class?: string;
+}
+
+export function ChatsIcon(props: ChatsIconProps): JSX.Element {
+	return (
+		<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256" fill="currentColor" class={props.class}>
+			<path d="M232,96a16,16,0,0,0-16-16H184V48a16,16,0,0,0-16-16H40A16,16,0,0,0,24,48V176a8,8,0,0,0,13,6.22L72,154V184a16,16,0,0,0,16,16h93.59L219,230.22a8,8,0,0,0,5,1.78,8,8,0,0,0,8-8Zm-42.55,89.78a8,8,0,0,0-5-1.78H88V152h80a16,16,0,0,0,16-16V96h32V207.25Z" />
+		</svg>
+	);
+}