Reconcile package.json version with v1.0.0 tag

[PAMulligan]

Problem

package.json currently declares "version": "0.5.0", but the only published git tag is v1.0.0. The two are out of sync, which makes it ambiguous which version is actually "released."

Goal

Pick a single source of truth (recommend git tags + commit-and-tag-version automation, matching Nerva) and bring package.json into alignment.

Acceptance criteria

• package.json version matches the latest published tag
• Release process documented in CONTRIBUTING.md (or equivalent)
• Future releases via pnpm run release keep both in sync automatically

Context

Found during a cross-repo versioning audit. Claudius has the same issue and is tracked separately.