Motivation

• Ensure Rust dependency updates are managed consistently and Renovate configuration is normalized.
• Prevent regressions by running cargo check across major platforms and deny warnings during CI.

Description

• Reformat .github/renovate.json, preserve packageRules for grouping cargo updates and automerge policies, and set ignoreTests to false.
• Add a new GitHub Actions workflow .github/workflows/ci.yml named Cross Platform Cargo Check that runs on push, pull_request, and manual dispatch.
• The workflow runs a matrix over macos-latest, windows-latest, and ubuntu-latest, adds the appropriate Rust targets, and uses cargo check --target ... --workspace --all-features with RUSTFLAGS: "-D warnings" to treat warnings as errors.
• Use dtolnay/rust-toolchain@stable to install Rust and Swatinem/rust-cache@v2 for caching in the workflow.

Testing

• Added the Cross Platform Cargo Check workflow which runs cargo check --target <matrix> --workspace --all-features and will run automatically on push and pull_request for main and dev branches.
• No automated workflow runs were executed as part of this change prior to submission of the PR.

Codex Task