feat(server): migrate copilot to native (#14620)

#### PR Dependency Tree


* **PR #14620** 👈

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**
* Native LLM workflows: structured outputs, embeddings, and reranking
plus richer multimodal attachments (images, audio, files) and improved
remote-attachment inlining.

* **Refactor**
* Tooling API unified behind a local tool-definition helper;
provider/adapters reorganized to route through native dispatch paths.

* **Chores**
* Dependency updates, removed legacy Google SDK integrations, and
increased front memory allocation.

* **Tests**
* Expanded end-to-end and streaming tests exercising native provider
flows, attachments, and rerank/structured scenarios.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

.cargo/config.toml

@@ -19,3 +19,8 @@ rustflags = [
 # pthread_key_create() destructors and segfault after a DSO unloading
 [target.'cfg(all(target_env = "gnu", not(target_os = "windows")))']
 rustflags = ["-C", "link-args=-Wl,-z,nodelete"]
+
+# Temporary local llm_adapter override.
+# Uncomment when verifying AFFiNE against the sibling llm_adapter workspace.
+# [patch.crates-io]
+# llm_adapter = { path = "../llm_adapter" }