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/fluxer_desktop/packaging/winget/Fluxer.Fluxer.installer.yaml

@@ -0,0 +1,19 @@
+PackageIdentifier: Fluxer.Fluxer
+PackageVersion: PLACEHOLDER_VERSION
+MinimumOSVersion: 10.0.17763.0
+InstallerType: nullsoft
+Scope: user
+InstallModes:
+  - interactive
+  - silent
+  - silentWithProgress
+UpgradeBehavior: install
+Installers:
+  - Architecture: x64
+    InstallerUrl: https://api.fluxer.app/dl/desktop/stable/win32/x64/PLACEHOLDER_VERSION/setup
+    InstallerSha256: PLACEHOLDER_SHA256_X64
+  - Architecture: arm64
+    InstallerUrl: https://api.fluxer.app/dl/desktop/stable/win32/arm64/PLACEHOLDER_VERSION/setup
+    InstallerSha256: PLACEHOLDER_SHA256_ARM64
+ManifestType: installer
+ManifestVersion: 1.6.0

fluxer/fluxer_desktop/packaging/winget/Fluxer.Fluxer.locale.en-US.yaml

@@ -0,0 +1,22 @@
+PackageIdentifier: Fluxer.Fluxer
+PackageVersion: PLACEHOLDER_VERSION
+PackageLocale: en-US
+Publisher: Fluxer Contributors
+PublisherUrl: https://fluxer.app
+PublisherSupportUrl: https://github.com/fluxerapp/fluxer/issues
+PackageName: Fluxer
+PackageUrl: https://fluxer.app
+License: AGPL-3.0-or-later
+LicenseUrl: https://github.com/fluxerapp/fluxer/blob/main/LICENCE
+ShortDescription: Instant messaging and VoIP application
+Description: Fluxer is a free and open-source instant messaging and voice-over-IP application. It provides text chat, voice calls, video calls, and screen sharing in a modern, privacy-respecting interface.
+Tags:
+  - chat
+  - messaging
+  - voip
+  - voice
+  - video
+  - communication
+  - open-source
+ManifestType: defaultLocale
+ManifestVersion: 1.6.0

fluxer/fluxer_desktop/packaging/winget/Fluxer.Fluxer.yaml

@@ -0,0 +1,5 @@
+PackageIdentifier: Fluxer.Fluxer
+PackageVersion: PLACEHOLDER_VERSION
+DefaultLocale: en-US
+ManifestType: version
+ManifestVersion: 1.6.0

fluxer/fluxer_desktop/packaging/winget/README.md

@@ -0,0 +1,33 @@
+# Fluxer Winget manifest
+
+Windows Package Manager (winget) manifest for installing Fluxer on Windows.
+
+## Placeholders
+
+The `PackageVersion` and `InstallerSha256` fields are set to placeholder values across all three manifest files. Update them before submitting to the winget-pkgs repository.
+
+## Manifest files
+
+- `Fluxer.Fluxer.yaml` -- version manifest (required)
+- `Fluxer.Fluxer.installer.yaml` -- installer details for x64 and arm64
+- `Fluxer.Fluxer.locale.en-US.yaml` -- default locale metadata
+
+## Validating
+
+```bash
+winget validate --manifest .
+```
+
+## Testing locally
+
+```bash
+winget install --manifest .
+```
+
+## Fetching the latest version
+
+```bash
+curl -s https://api.fluxer.app/dl/desktop/stable/win32/x64/latest | jq
+```
+
+This returns a JSON object containing `version`, `pub_date`, and `files` with download URLs and SHA256 checksums for each format.