build: inherit prefill-router from the workspace

[nachiketb-nvidia]

What

• Declare prefill-router in the workspace dependency table.
• Keep the runner dependency optional and inherit its path and version from the workspace.
• Preserve the existing prefill-router feature.

Why

prefill-router is already a workspace member. Its path and version should have one source of truth, like the other shared crates. This keeps Git-based Cargo installs and workspace builds on the same dependency declaration.

The crates.io publication order remains handled by #707 because optional registry dependencies must still be published.

Related to SWITCH-1444.

How

The root manifest owns the versioned path dependency. switchyard-runner inherits it with workspace = true and keeps optional = true.

Validation

• cargo metadata --locked --no-deps --format-version 1
• cargo check --locked -p switchyard-runner --features prefill-router
• cargo +1.96.1 install --git https://github.com/NVIDIA-NeMo/Switchyard.git --branch nachiketb/build-workspace-prefill-dependency --locked --root /tmp/switchyard-git-install-default switchyard-server
• /tmp/switchyard-git-install-default/bin/switchyard-server --help

The GitHub install completed and the installed executable ran successfully.

Summary by CodeRabbit

• Chores
  • Updated internal dependency management for the prefill routing component.
  • No user-facing features or behavior changes are included in this update.

[github-actions]

PR Preview Action v1.8.1
🚀 View preview at https://NVIDIA-NeMo.github.io/Switchyard/pr-preview/pr-710/
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[coderabbitai]

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Reviewing files that changed from the base of the PR and between f27abd6 and fc7c20f.

📒 Files selected for processing (2)

• Cargo.toml
• crates/switchyard-runner/Cargo.toml

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Walkthrough

The workspace now defines prefill-router version 0.2.0. switchyard-runner uses this workspace dependency while keeping it optional.

Changes

Workspace Dependency Configuration

Layer / File(s)	Summary
Workspace dependency wiring Cargo.toml, crates/switchyard-runner/Cargo.toml	The workspace adds the path dependency. switchyard-runner replaces its local dependency declaration with the workspace configuration.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to fc7c2

The dependency centralization preserves the existing feature-enabled and feature-disabled build paths, with no merge-blocking risk identified.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: moving the prefill-router dependency configuration to the workspace.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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_{A rabbit hops through Cargo’s gate
prefill-router now shares one state
The workspace holds version two
The runner keeps its option true
Clean paths guide the build along}

_{Comment @coderabbitai help to get the list of available commands.}