fulfillr-dev: staging back-office container + Turso store prep

Add a second go-fulfillr container (fulfillr-dev) wired to the staging
Turso store + EasyPost/Stripe test keys via dev.json, served at
fulfillr-dev.debyltech.com (Caddy -> :9055), LAN-restricted like prod.

- fulfillr-dev.yml + dev.json.j2: the staging container, volumes, config
- defaults: fulfillr_dev_* vars; prod store URL stubbed off until cutover
- Caddyfile + caddy.yml: fulfillr-dev site block and static mount
- awsddns.yml: Route53 DDNS for the fulfillr-dev hostname
- production.json.j2: add store_database_url/store_auth, rename stripe key
  var to fulfillr_stripe_api_key
- vault.yml: dev + store/stripe secrets

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ansible/roles/podman/templates/fulfillr/production.json.j2

@@ -1,10 +1,12 @@
 {
   "snipcart_api_key": "{{ snipcart_api_key }}",
   "easypost_api_key": "{{ easypost_api_key }}",
-  "stripe_api_key": "{{ stripe_api_key }}",
+  "stripe_api_key": "{{ fulfillr_stripe_api_key }}",
   "backinstock_table": "{{ fulfillr_backinstock_table }}",
   "cases_table": "{{ fulfillr_cases_table }}",
   "tickets_table": "{{ fulfillr_tickets_table }}",
+  "store_database_url": "{{ fulfillr_store_database_url }}",
+  "store_auth_token": "{{ fulfillr_store_auth_token }}",
   "aws": {
     "access_key": "{{ fulfillr_access_key }}",
     "secret_key": "{{ fulfillr_secret_key }}",