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/.github/workflows/sync-static.yaml

@@ -0,0 +1,42 @@
+name: sync static-bucket
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'fluxer_static/**'
+  workflow_dispatch:
+
+concurrency:
+  group: sync-fluxer-static
+  cancel-in-progress: true
+
+jobs:
+  push:
+    runs-on: ubuntu-latest
+    timeout-minutes: 25
+    permissions:
+      contents: read
+    env:
+      RCLONE_REMOTE: ovh
+      RCLONE_BUCKET: fluxer-static
+      RCLONE_SOURCE: fluxer_static
+      RCLONE_ENDPOINT: https://s3.us-east-va.io.cloud.ovh.us
+      RCLONE_REGION: us-east-1
+      RCLONE_SOURCE_DIR: fluxer_static
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          lfs: true
+          fetch-depth: 0
+
+      - name: Install rclone
+        run: python3 scripts/ci/workflows/sync_static.py --step install_rclone
+
+      - name: Push repo contents to bucket
+        env:
+          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+        run: python3 scripts/ci/workflows/sync_static.py --step push