fix: decouple command contract from release version

[corwinm]

Summary

• removes the package release version from the generated CLI command contract
• bumps the command contract schema from version 1 to version 2
• keeps runtime arashi --version sourced from package.json
• adds regressions proving contract output does not change when only the runtime release version changes

Why

Semantic-release changes package.json in a skipped release commit. Because the command contract duplicated that version, every release made the contract stale even when the command surface was unchanged. The next unrelated PR then failed the freshness gate.

Related coordination

• Meta/OpenSpec PR: fix: decouple command contract from release version arashi-arashi#221

Validation

• pnpm run format
• pnpm run lint — passes with existing warnings only
• pnpm run typecheck
• pnpm run schema:check
• pnpm run contract:check
• pnpm run test — 969 passed, 1 skipped
• pnpm run build
• built arashi --version smoke check — 1.20.1
• independent review — no blocking findings