Expose available access programs in model discovery (#44893)

## What changed

Carry optional `available_access_programs` metadata through model information, presets, caches, and the TUI, and expose it as `availableAccessPrograms` in app-server `model/list` responses. Update the generated JSON schemas, TypeScript types, and Python models.

Preserve the distinction between missing metadata and an empty `cyber` list. Ignore unknown cyber program names when reading the catalog so new server programs do not prevent older clients from loading it. Discovery metadata does not grant access; inference still enforces authorization.

## Testing

Add coverage for absent, null, empty, and populated metadata, unknown program names, and app-server serialization. Extend cache tests and verify that online refreshes persist changed access metadata even when the catalog ETag stays unchanged.

GitOrigin-RevId: b3ef5805c1c61b8d64b9b896c9c0a79120143667

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -11162,6 +11162,18 @@
             }
           ]
         },
+        "availableAccessPrograms": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/ModelAccessPrograms"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "Null when the catalog does not provide access-program metadata."
+        },
         "defaultReasoningEffort": {
           "$ref": "#/definitions/ReasoningEffort"
         },
@@ -11265,6 +11277,22 @@
       ],
       "type": "object"
     },
+    "ModelAccessPrograms": {
+      "description": "Caller-specific explicit access programs advertised by model discovery.",
+      "properties": {
+        "cyber": {
+          "description": "Accepted explicit selections.",
+          "items": {
+            "$ref": "#/definitions/CyberAccessProgram"
+          },
+          "type": "array"
+        }
+      },
+      "required": [
+        "cyber"
+      ],
+      "type": "object"
+    },
     "ModelAvailabilityNux": {
       "properties": {
         "message": {