feat(server): converge legacy compatibility (#15426)

#### PR Dependency Tree


* **PR #15426** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added workspace BYOK profiles with provider/model catalogs, capability
validation, connection probing, credential rotation, reordering, and
secure local leases.
* Added Copilot route options, selectable targets, managed tiers,
explicit profile/model overrides, and improved streaming with tool
callbacks and abort support.
* Added Copilot availability controls to prevent access when the feature
is disabled.
* **Changes**
* Simplified Copilot configuration and removed legacy provider-specific
settings.
* Removed obsolete model, token-cost, transcript strategy, and provider
metadata fields from public responses.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/native/src/llm/mod.rs

@@ -1,19 +1,17 @@
 mod action;
+pub(crate) mod byok;
 mod contract_schema;
 mod core;
 mod ffi;
-mod host;
 mod prompt_catalog;
+pub(crate) mod route;
 
-#[cfg(test)]
-mod tests;
-
-pub use core::{
-  capability::{llm_match_model_capabilities, llm_resolve_requested_model_match},
+pub use self::core::{
+  capability::llm_match_model_capabilities,
   model_registry::{llm_match_model_registry, llm_resolve_model_registry_variant},
   prompt::{
-    llm_collect_prompt_metadata, llm_count_prompt_tokens, llm_get_built_in_prompt_spec, llm_list_built_in_prompt_specs,
-    llm_render_built_in_prompt, llm_render_built_in_session_prompt, llm_render_prompt, llm_render_session_prompt,
+    llm_get_built_in_prompt_spec, llm_list_built_in_prompt_specs, llm_render_built_in_prompt,
+    llm_render_built_in_session_prompt,
   },
   request_builder::{
     llm_build_canonical_request, llm_build_canonical_structured_request, llm_build_embedding_request,
@@ -22,29 +20,34 @@ pub use core::{
   structured_output::{llm_canonical_json_schema_hash, llm_validate_json_schema},
 };
 
-pub use action::run_native_action_recipe_prepared_stream;
-pub use contract_schema::{
-  llm_compile_execution_plan, llm_get_contract_schema, llm_normalize_prepared_routes, llm_validate_contract,
+pub use action::copilot_action_recipe;
+pub use byok::{
+  ByokCapabilityInput, ByokCatalogModelOutput, ByokCatalogOutput, ByokCatalogProviderOutput, ByokEndpointInput,
+  ByokLocalLeaseOutput, ByokModelDeclarationInput, ByokModelProbeCheckOutput, ByokModelProbeOutput,
+  ByokProbeCheckInput, ByokProbeResultOutput, ByokProbeStatusOutput, ByokProfileDefinitionInput, ByokProfileOutput,
+  ByokValidationOutput, CreateByokLocalLeaseInput, CreateByokLocalLeaseProviderInput, CreateByokProfileInput,
+  ProbeByokDraftInput, ProbeByokProfileInput, ReorderByokProfilesInput, ReplaceByokProfileInput,
+  RotateByokCredentialInput, byok_catalog,
 };
-#[cfg(test)]
-pub(crate) use ffi::{AsyncLlmDispatchPreparedTask, resolve_request_chain};
+
+#[napi_derive::napi(catch_unwind)]
+pub fn llm_get_byok_catalog() -> ByokCatalogOutput {
+  byok_catalog()
+}
+pub(crate) use byok::{ByokProfileDefinition, validate_definition};
+pub use contract_schema::{llm_get_contract_schema, llm_validate_contract};
 pub(crate) use ffi::{
-  LlmDispatchPayload, LlmEmbeddingDispatchPayload, LlmMiddlewarePayload, LlmPreparedImageDispatchRoutePayload,
-  LlmRerankDispatchPayload, LlmRoutedBackendPayload, LlmStructuredDispatchPayload, StreamPipeline,
-  apply_request_middlewares, apply_structured_request_middlewares, backend_transport_error,
-  dispatch_prepared_image_route_payloads, dispatch_prepared_structured_routes, map_backend_error, map_json_error,
-  parse_embedding_protocol, parse_prepared_chat_routes_with_middleware, parse_prepared_chat_routes_without_middleware,
-  parse_protocol, parse_rerank_protocol, parse_structured_protocol, resolve_stream_chain,
+  LlmDispatchPayload, LlmMiddlewarePayload, LlmRerankDispatchPayload, LlmStructuredDispatchPayload,
 };
-pub use ffi::{
-  llm_dispatch_prepared, llm_embedding_dispatch, llm_embedding_dispatch_prepared, llm_image_dispatch_prepared,
-  llm_plan_attachment_reference, llm_rerank_dispatch, llm_rerank_dispatch_prepared, llm_resolve_request_intent,
-  llm_structured_dispatch, llm_structured_dispatch_prepared,
-};
-pub(crate) use host::{
-  LlmStreamHandle, STREAM_ABORTED_REASON, STREAM_CALLBACK_DISPATCH_FAILED_REASON, STREAM_END_MARKER, emit_error_event,
-};
-pub use host::{
-  llm_dispatch_prepared_stream, llm_dispatch_tool_loop_stream, llm_dispatch_tool_loop_stream_prepared,
-  llm_dispatch_tool_loop_stream_routed,
+pub use prompt_catalog::llm_get_built_in_route_options;
+pub use route::{
+  CopilotAccessProjection, CopilotExecuteInput, CopilotManagedTier, CopilotRouteCheckInput, CopilotTargetOverrideInput,
 };
+
+pub(crate) fn invalid_arg(message: impl Into<String>) -> napi::Error {
+  napi::Error::new(napi::Status::InvalidArg, message.into())
+}
+
+pub(crate) fn map_json_error(error: serde_json::Error) -> napi::Error {
+  invalid_arg(error.to_string())
+}