Split release preparation commit behavior

[mcmire]

Summary

• Split release commit behavior by workflow
• Non-interactive release preparation keeps separate commits, ending with Filter release to only selected packages
• Rename the non-interactive initialization commit to Initialize release X.Y.Z by bumping all packages
• Interactive release preparation creates one Release X.Y.Z commit without creating and soft-resetting a prior commit
• Add focused UI coverage for interactive branch preparation and finalization
• Add an unreleased changelog entry

Testing

• yarn jest --no-coverage src/monorepo-workflow-operations.test.ts src/functional.test.ts src/ui.test.ts src/repo.test.ts (expected failure after test-only update)
• yarn jest --no-coverage src/monorepo-workflow-operations.test.ts src/functional.test.ts src/ui.test.ts src/repo.test.ts
• yarn lint
• yarn test