codex: keep full access justification requirements-only

Remove the app-server protocol and schema exposure for require_full_access_justification so the flag stays internal to requirements.toml loading and runtime enforcement.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server-protocol/schema/json/v2/ConfigRequirementsReadResponse.json

@@ -98,12 +98,6 @@
             "object",
             "null"
           ]
-        },
-        "requireFullAccessJustification": {
-          "type": [
-            "boolean",
-            "null"
-          ]
         }
       },
       "type": "object"