feat(machine): operator branding — local-file source (issue #47 V1)

Read /var/lib/bitspire/branding/{logo.png,branding.json} on startup and
apply across the renderer. branding.json may set title, theme (one of
the 6 built-ins or "custom"), and a custom_colors map (with optional
.dark overlay) — unset CSS vars fall back to gruvbox.

Wiring:
- electron/main.ts:loadBranding() reads + validates the JSON and
  base64-encodes logo.png; surfaced via the existing get-config IPC
- composables/useBranding.ts holds reactive logoUrl/title refs and a
  single setBranding() setter — the seam where #48's Nostr-event
  source will eventually overlay the local-file source
- composables/useTheme.ts:applyBrandingTheme() handles built-in theme
  swap and injects a <style#branding-custom-theme> block for custom
- IdleView binds :src/title; App.vue calls setBranding() before the
  maintenance screen renders so "Under Service" wears operator branding

Provisioning: new deploy/nixos/provision-branding.sh rsyncs a local dir
to /var/lib/bitspire/branding/ via sudo-on-the-far-side and restarts
bitspire.service. The existing provision-atm.sh stays focused on .env.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/nixos/provision-branding.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+# Provision operator branding (logo + branding.json) to a deployed bitSpire ATM.
+# Composes with provision-atm.sh — that one wires LNbits creds, this one wires
+# operator look-and-feel. Per issue #47.
+#
+# Usage:
+#   bash provision-branding.sh <branding-dir>                       # SSH to localhost:2222 (QEMU)
+#   bash provision-branding.sh <branding-dir> 192.168.1.50          # SSH to a real ATM on the LAN
+#   bash provision-branding.sh <branding-dir> 192.168.1.50 22       # custom SSH port
+#
+# Expected files in <branding-dir>:
+#   logo.png         — operator logo (any reasonable size; rendered ~12vh)
+#   branding.json    — { title, theme, custom_colors{...}, custom_colors.dark{...} }
+#
+# Either file is optional; the on-disk schema in /var/lib/bitspire/branding/
+# matches whatever <branding-dir> contains (rsync --delete).
+set -euo pipefail
+
+BRANDING_DIR="${1:-}"
+ATM_HOST="${2:-localhost}"
+ATM_SSH_PORT="${3:-2222}"
+ATM_USER="bitspire"
+REMOTE_DIR="/var/lib/bitspire/branding"
+
+if [ -z "$BRANDING_DIR" ]; then
+    echo "Usage: $0 <branding-dir> [host] [port]" >&2
+    echo "       $0 ./acme-brand                       (QEMU on localhost:2222)" >&2
+    echo "       $0 ./acme-brand 192.168.1.50          (real ATM)" >&2
+    exit 1
+fi
+
+if [ ! -d "$BRANDING_DIR" ]; then
+    echo "ERROR: branding directory not found: $BRANDING_DIR" >&2
+    exit 1
+fi
+
+echo "=== Provisioning branding to $ATM_HOST:$ATM_SSH_PORT ==="
+echo "Local dir : $BRANDING_DIR"
+echo "Remote dir: $REMOTE_DIR"
+echo ""
+
+# Show what we're about to push so the operator can sanity-check before sync.
+ls -la "$BRANDING_DIR"
+echo ""
+
+# rsync over SSH. --delete to clean stale files (a removed logo.png should
+# disappear, not linger). sudo on the remote side because /var/lib/bitspire
+# is owned by the bitspire service user, not the SSH user.
+rsync -avz --delete \
+    --rsync-path="sudo rsync" \
+    -e "ssh -o StrictHostKeyChecking=no -p $ATM_SSH_PORT" \
+    "$BRANDING_DIR/" \
+    "$ATM_USER@$ATM_HOST:$REMOTE_DIR/"
+
+# Restart the service so loadBranding() re-runs and the renderer picks up the
+# new files. V2 (Nostr-event source) will eliminate the restart need.
+ssh -o StrictHostKeyChecking=no -p "$ATM_SSH_PORT" "$ATM_USER@$ATM_HOST" \
+    "sudo systemctl restart bitspire"
+
+echo ""
+echo "=== Branding provisioned. Service restarted. ==="