chore: bump prerelease version to 0.1.4-rc.0

[jesse-black]

Motivation

• Prepare a prerelease of the crate by advancing the package version to a new prerelease identifier so releases and packaging workflows target the intended pre-release artifact.

Description

• Update the package version in Cargo.toml from 0.1.3 to 0.1.4-rc.0 and update the covgate entry in Cargo.lock to match 0.1.4-rc.0 so the lockfile is consistent with the manifest.

Testing

• Run cargo xtask validate, which exercised formatting, clippy, the full test suite, coverage validation, and dependency checks, and completed successfully (all checks passed).

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Codex Task