Updates catalog schema metadata and required fields

Reflects schema version bump to 0.9.2 and updates the description with the latest modification date. Replaces the revision number field with a Unix timestamp in seconds for last generation at updated_at.

Author: CSchmidtDD

src/schemas/catalog.schema.json

@@ -1,10 +1,10 @@
 {
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://service-discovery.prod.ti-platform.de/schema/catalog.schema.json",
-  "title": "TI Service Catalog",
-  "description": "Machine-readable catalog of Telematikinfrastruktur service instances and routing rules.",
+  "title": "TI Service Catalog Version 0.9.2",
+  "description": "Machine-readable catalog of Telematikinfrastruktur service instances and routing rules. Last updated 26.03.2026",
   "type": "object",
-  "required": ["format_version", "revision", "env", "service_instances"],
+  "required": ["format_version", "updated_at", "env", "service_instances"],
   "additionalProperties": false,
   "properties": {
     "format_version": {
@@ -13,15 +13,15 @@
       "description": "Semantic version of the catalog format.",
       "examples": ["1.0.0"]
     },
-    "revision": {
+    "updated_at": {
       "type": "integer",
-      "minimum": 1,
-      "description": "Monotonically increasing revision number. Incremented on every change."
+      "minimum": 1774508400,
+      "description": "Unix Epoch Timestamp from the moment this file was last generated. Shall be updated when higher than previous value."
     },
     "env": {
       "type": "string",
-      "enum": ["dev", "test", "ref", "prod"],
-      "description": "Target environment. One catalog file per environment."
+      "enum": ["gemdev","dev", "test", "ref", "prod"],
+      "description": "Target instance. One catalog file per instance."
     },
     "service_instances": {
       "type": "object",