Add booking stack, client deploys, and back-office updates

- deploy/booking: shared Easy!Appointments stack with brand-matched
  wizard (flatpickr recolor, single-tenant provider hide, iframe
  auto-fit height reporter)
- deploy/clients: per-client isolated nginx compose stacks with
  _template scaffold, new-client.sh, and happynails live site
- deploy/backup: smb-db backup script
- n8n: booking-sync workflow; onboarding tweaks
- playbooks: lead-to-customer lifecycle + outreach
- templates: nail-studio landing previews
- backoffice: app/db/init/compose updates

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

deploy/clients/new-client.sh

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+# Scaffold a new ISOLATED client stack from _template/.
+#
+# Usage: ./new-client.sh <slug> <domain> [source-site-dir]
+#   ./new-client.sh happynails happynails.de ../../templates/landing/preview-happynails
+#
+# Creates deploy/clients/<slug>/ with its own .env + site/, then prints the
+# Caddy block and the deploy command. Run it from deploy/clients/.
+set -euo pipefail
+cd "$(dirname "$0")"
+
+SLUG="${1:?usage: new-client.sh <slug> <domain> [source-site-dir]}"
+DOMAIN="${2:?domain required (e.g. happynails.de)}"
+SRC="${3:-}"
+
+[[ "$SLUG" =~ ^[a-z0-9-]+$ ]] || { echo "slug must be lowercase letters/digits/dashes"; exit 1; }
+[ -e "$SLUG" ] && { echo "client '$SLUG' already exists at deploy/clients/$SLUG"; exit 1; }
+
+cp -r _template "$SLUG"
+cat > "$SLUG/.env" <<EOF
+CLIENT_SLUG=$SLUG
+CLIENT_DOMAIN=$DOMAIN
+EOF
+
+if [ -n "$SRC" ]; then
+  [ -d "$SRC" ] || { echo "source dir '$SRC' not found"; exit 1; }
+  rm -f "$SLUG"/site/*.html
+  cp -r "$SRC"/. "$SLUG"/site/
+  echo "Seeded site/ from $SRC"
+fi
+
+cat <<EOF
+
+✓ Created deploy/clients/$SLUG
+
+1) Add this block to the homelab Caddyfile, then reload Caddy:
+   docker exec caddy caddy reload --config /etc/caddy/Caddyfile
+
+   $DOMAIN {
+       reverse_proxy client-$SLUG:80
+       encode zstd gzip
+   }
+
+2) DNS: a *.mivanchenko.de subdomain already resolves (wildcard) — nothing to do.
+   For a client-owned domain, add their A record $DOMAIN -> 188.193.49.3.
+
+3) Deploy the stack:
+   scp -r $SLUG mivanchenko@mivanchenko.de:/home/mivanchenko/clients/
+   ssh mivanchenko@mivanchenko.de 'cd ~/clients/$SLUG && docker compose up -d'
+
+Remove this client later (isolated — touches nothing else):
+   ssh mivanchenko@mivanchenko.de 'cd ~/clients/$SLUG && docker compose down'
+EOF