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>

backoffice/app/db.py

@@ -21,7 +21,7 @@ TABLES = {
         "cols": ["client_id", "business_name", "owner_name", "email", "phone",
                  "niche", "tier", "status", "domain", "stack_notes", "vault_ref",
                  "services", "billing_cycle", "monthly_fee_eur", "start_date",
-                 "renewal_date", "created_at", "notes"],
+                 "renewal_date", "created_at", "notes", "notify_channel"],
         "dates": ["start_date", "renewal_date"],
         "timestamps": ["created_at"],
         "numbers": ["monthly_fee_eur"],
@@ -101,6 +101,12 @@ def parse_ts(v):
     if isinstance(v, datetime):
         return v
     s = str(v).strip()
+    # ISO-8601 / RFC3339 (incl. trailing Z and +hh:mm offsets — what Google
+    # Calendar / booking tools emit). fromisoformat handles Z on Python 3.11+.
+    try:
+        return datetime.fromisoformat(s.replace("Z", "+00:00"))
+    except ValueError:
+        pass
     for fmt in ("%Y-%m-%d %H:%M:%S", "%Y-%m-%d %H:%M", "%Y-%m-%dT%H:%M:%S",
                 "%Y-%m-%dT%H:%M", "%Y-%m-%d"):
         try: