valia-sites: registry stack for Valia's Pages sites + declarative internal DNS (ADR-0018)

Valia keeps asking Viktor to host 1-page sites from her Drive folders;
this makes it one map entry. New stacks/valia-sites: per site a CF Pages
project + custom domain + proxied CNAME (bridge adopted via import{}),
a ConfigMap feed (valia-sites-dns) the technitium ingress-dns-sync
script now reconciles internal CNAMEs from (add/update/REMOVE — fixes
the add-only stale-record gotcha), and one shared 10-min CronJob that
mirrors each Content folder (rclone, drive.readonly, stem95su's guards)
and wrangler-deploys ONLY on manifest change (free-tier deploy cap).
Scoped CF Pages token + shared rclone conf in secret/valia-sites; the
Global API Key never enters a pod. cloudflared forgets bridge's record
via removed{} (no destroy). stem95su is in the map dns-parked
(manage_dns=false) until its cutover commit.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

stacks/valia-sites/variables.tf

@@ -0,0 +1,3 @@
+variable "cloudflare_zone_id" {
+  type = string
+}