chore: regenerate public API snapshot for new adagents validator exports

Adds AdagentsEntryError, AdagentsValidationReport, EntryErrorKind, and
validate_adagents_structure to the snapshot — all intentional additions
in this PR.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: bokelley

tests/fixtures/public_api_snapshot.json

@@ -27,9 +27,11 @@
     "ActivateSignalResponse",
     "ActivateSignalSuccessResponse",
     "AdAgentsValidationResult",
+    "AdagentsEntryError",
     "AdagentsNotFoundError",
     "AdagentsTimeoutError",
     "AdagentsValidationError",
+    "AdagentsValidationReport",
     "AdvertiserIndustry",
     "AgentCapabilities",
     "AgentCompliance",
@@ -115,6 +117,7 @@
     "DiscoveryMethod",
     "DomainLookupResult",
     "Duration",
+    "EntryErrorKind",
     "Error",
     "ErrorCode",
     "EventType",
@@ -373,6 +376,7 @@
     "uses_deprecated_assets_field",
     "validate_adagents",
     "validate_adagents_domain",
+    "validate_adagents_structure",
     "validate_agent_authorization",
     "validate_capabilities",
     "validate_product",