Health-Check: DNS-over-HTTPS-Rückfall bei nicht auflösbarem Hostnamen, DNS-Problem des Admin-Servers nur Warnung (außer strikte Rollouts); COST_INGEST_KEY optional (Schema-getrieben)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

vendor/platform/CORE_VERSION

@@ -1 +1 @@
-13055b811ca0030841f41ce1f10e4f30cba1a7db admin-platform-integration
+d6e72060858f584661bafc6396d40319b11e5afc admin-platform-integration

vendor/platform/core/BUILD_INFO.json

@@ -1 +1 @@
-{"sha": "13055b811ca0030841f41ce1f10e4f30cba1a7db", "built_at": "2026-10-15T13:26:28Z"}
+{"sha": "d6e72060858f584661bafc6396d40319b11e5afc", "built_at": "2026-10-15T14:36:00Z"}

vendor/platform/core/schema/tenant_schema.json

@@ -813,12 +813,11 @@
       "name": "COST_INGEST_KEY",
       "kind": "secret",
       "scope": "tenant",
-      "label": "Cost-Ingest-Key",
-      "help": "Schlüssel für die Kostenerfassung.",
+      "label": "Cost-Ingest-Key (optional)",
+      "help": "Optional – ohne Key bleibt die Kostenerfassung inaktiv (core/cost.py).",
       "default": null,
       "group": "Secrets",
-      "setting": "cost_ingest_key",
-      "required": true
+      "setting": "cost_ingest_key"
     },
     {
       "name": "TENANT",