feat(workspace): expose lifecycle command authority

[decode2]

Linked issue

Closes #56

• The linked issue has the status:approved label.

Pull request type

• New feature (type:feature)

Summary

• Atomically exposes all seven prepared workspace lifecycle commands.
• Keeps handler registration, build manifests, permissions, platform capabilities, generated contracts, and parity tests synchronized.

Changes

Area	Change
Tauri handler/build manifest	Registers seven finite workspace commands.
Permissions and capabilities	Grants matching Windows/Linux terminal authority.
Generated contracts	Adds seven allow/deny command contracts.
Authority tests	Verifies exact normal/CRLF and platform parity.

Test plan

• Authority manifest tests: 3/3.
• Desktop workspace tests: 8/8; real PTY reachability: 1/1.
• Native and Windows GNU cargo checks passed; fmt and diff checks passed.

Chained pull request context

• Previous PR: feat(workspace): wire lifecycle commands #55
• Next PR: PR12 — React workspace lifecycle UI
• Review this PR first: atomic command registration and finite authority parity
• Intentionally out of scope: React UI, packaging, CI expansion, and release documentation

Contributor checklist

• I searched for duplicate issues and pull requests before starting.
• I linked an approved issue.
• I selected exactly one type and will apply exactly one matching label.
• I included reproducible evidence.
• Documentation is deferred to the release-evidence slice.
• Commits follow Conventional Commits.
• No AI attribution or Co-Authored-By trailers.