feat(gateway): harden provider request execution

Preserve exact request payloads and model client surface and API operation explicitly.

Add Anthropic compatibility profiles, bounded stream commitment, and scoped OAuth retry behavior across provider transports.

crates/aether-provider/transport/src/lib.rs

@@ -1,4 +1,5 @@
 mod agent_identity;
+mod anthropic_compat;
 pub mod antigravity;
 pub mod auth;
 mod auth_config;
@@ -46,6 +47,10 @@ pub use agent_identity::{
     CODEX_AGENT_IDENTITY_AUTH_MODE, CODEX_AGENT_IDENTITY_CACHED_ENTRY_PROVIDER_TYPE,
     CODEX_AGENT_IDENTITY_PROVIDER_TYPE, CODEX_AGENT_IDENTITY_TASK_REGISTRATION_REQUEST_ID,
 };
+pub use anthropic_compat::{
+    resolve_anthropic_compatibility_profile, validate_anthropic_compatibility_profile_config,
+    AnthropicCompatibilityProfile, AnthropicCompatibilityProfileConfigError,
+};
 pub use auth::{build_passthrough_headers, ensure_upstream_auth_header};
 pub use auth_config::apply_local_auth_config_header_overrides;
 pub use cache::{provider_transport_snapshot_looks_refreshed, ProviderTransportSnapshotCacheKey};
@@ -76,6 +81,7 @@ pub use gemini_files::{
     GeminiFilesRequestBodyError, GeminiFilesRequestBodyParts,
 };
 pub use generic_oauth::{
+    resolve_local_generic_oauth_transport_authorization,
     supports_local_generic_oauth_request_auth_resolution, GenericOAuthRefreshAdapter,
 };
 pub use grok::{
@@ -122,7 +128,7 @@ pub use request_url::{
     build_kiro_cross_format_upstream_url, build_local_openai_chat_upstream_url,
     build_local_openai_responses_upstream_url, build_transport_request_url,
     build_transport_request_url_for_request_body, gemini_embedding_request_body_uses_batch,
-    TransportRequestUrlParams,
+    transport_supports_api_operation, TransportRequestUrlParams,
 };
 pub use rules::{
     apply_local_body_rules, apply_local_body_rules_with_request_headers, apply_local_header_rules,
@@ -134,6 +140,8 @@ pub use same_format_provider::{
     build_same_format_provider_headers, build_same_format_provider_request_body,
     build_same_format_provider_request_body_with_compatibility_report,
     build_same_format_provider_upstream_url, classify_same_format_provider_request_behavior,
+    classify_same_format_provider_request_behavior_for_operation,
+    enforce_same_format_provider_api_operation_body_policy,
     resolve_same_format_provider_direct_auth, same_format_provider_transport_supported,
     same_format_provider_transport_unsupported_reason,
     same_format_provider_transport_unsupported_reason_for_trace,