refactor(switchyard): remove built-in service integration

[bbednarski9]

Overview

Remove the built-in, service-backed Switchyard integration after its supported behavior moved to the external nvidia.switchyard native dynamic plugin.

• I confirm this contribution is my own work, or I have the right to submit it under this project's license.
• I searched existing issues and open pull requests, and this does not duplicate existing work.

Details

• Removes the nemo-relay-switchyard workspace crate, CLI switchyard Cargo feature, static component registration/editor support, service process E2E, and service-launching examples.
• Removes switchyard-translation from Relay's dependency graph and crates.io release inventory.
• Rejects legacy [[components]] kind = "switchyard" configuration with migration guidance for the nvidia.switchyard native API v2 plugin.
• Rewrites the Switchyard documentation around installing a trusted binary bundle and configuring it through [[plugins.dynamic]].
• Regenerates Cargo.lock and ATTRIBUTIONS-Rust.md.

This PR is intentionally independent from the ABI implementation branch, but must not merge before:

• Relay feat(plugin): add core-managed LLM continuations to native C ABI v2 #594 provides native dynamic plugin API v2.
• NVIDIA-NeMo/Switchyard test: validate OpenClaw hook-only fallback exports #220 provides the external switchyard-nemo-relay-plugin bundle.

The external plugin has already passed fake-provider process E2E and live Inference Hub routing through the ABI v2 branch. The live run produced 12 routing-requested and 12 routing-decision marks across two models in Phoenix project nemo-relay-switchyard-dynamic-plugin-20260730.

Validation:

• cargo check -p nemo-relay-cli --all-targets
• cargo test -p nemo-relay-cli --lib plugins::tests::editor_
• cargo test -p nemo-relay-cli --lib plugins::tests::component_
• cargo test -p nemo-relay-cli --lib server::tests::serve_listener_activates_
• cargo test -p nemo-relay-cli --lib plugins::tests::validate_config_rejects_removed_switchyard_component_with_migration_guidance -- --exact
• cargo clippy -p nemo-relay-cli --all-targets -- -D warnings
• cargo deny check
• cargo fmt --all -- --check
• pre-commit copyright, YAML, TOML, whitespace, lockfile, Rust attribution, Actionlint, and Lychee checks

The unrestricted full CLI unit binary currently reports unrelated failures caused by user-level configuration leaking into configuration assertions and the resulting poisoned global test lock. The focused code paths changed here pass independently.

Breaking change: Relay no longer ships or publishes the built-in nemo-relay-switchyard service integration. Existing service configuration must migrate to the external native API v2 plugin.

Where should the reviewer start?

Start with crates/cli/src/server/mod.rs for the legacy-configuration migration error, then review docs/configure-plugins/switchyard/about.mdx for the operator migration path. The remaining changes remove the old crate and its build, release, test, and example surfaces.

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• Relates to feat(plugin): add core-managed LLM continuations to native C ABI v2 #594
• Relates to feat(plugin): add NeMo Relay dynamic integration NVIDIA-NeMo/Switchyard#220

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[github-actions]

Fern docs preview: https://nvidia-preview-pull-request-595.docs.buildwithfern.com/nemo/relay/dev

[github-actions]

License Diff

Compared against origin/main.

Lockfile license changes

Lockfile License Changes

Rust

Added

• None

Removed

• switchyard-protocol 0.1.0 (Apache-2.0)
• switchyard-translation 0.1.0 (Apache-2.0)

Updated/Changed

• None

Node

Added

• None

Removed

• None

Updated/Changed

• None

Python

Added

• None

Removed

• None

Updated/Changed

• None

Status output

[license-diff] selected languages: rust, node, python
[license-diff] generating current inventory
[license-diff] current: generating Rust inventory
[license-diff] current: Rust inventory complete (447 packages)
[license-diff] current: generating Node inventory
[license-diff] current: Node inventory complete (367 packages)
[license-diff] current: generating Python inventory
[license-diff] current: Python inventory complete (105 packages)
[license-diff] current inventory complete
[license-diff] checking out base ref origin/main into a temporary worktree
[license-diff] base: generating Rust inventory
[license-diff] base: Rust inventory complete (449 packages)
[license-diff] base: generating Node inventory
[license-diff] base: Node inventory complete (367 packages)
[license-diff] base: generating Python inventory
[license-diff] base: Python inventory complete (105 packages)
[license-diff] base inventory complete
[license-diff] removing temporary base worktree
[license-diff] comparing inventories
[license-diff] rendering Markdown output
[license-diff] done