fix: make clone progress visible

[YogliB]

Summary

What

Make clone progress visible during long-running degit runs by emitting a CLONING lifecycle event before work starts and delaying SUCCESS until all tar/post-clone work is complete.

Why

Issue #220 reports that successful clones can look hung because the success line appears before the CLI is actually done.

Changes

• Added a CLONING info event in src/index.ts so the CLI can show that work has started.
• Moved the SUCCESS emission to the end of the clone flow so it reflects completion after tar extraction and post-clone directives.
• Added a regression test in test/unit/index.test.ts that proves CLONING happens before directive cleanup and SUCCESS.

Testing

How you verified this (commands, scenarios, or N/A):

• Focused unit tests: bun run test test/unit/index.test.ts

• Focused unit tests: bun run test test/unit/bin.test.ts

• CLI check: node degit rollup/rollup rollup

• Automated tests (bun run test)

• Manual / CLI check if user-facing behavior changed

• CI passes

Review notes

Breaking changes (or none)

None.

Risks / rollout (or none)

The new start event is intentionally minimal; the main risk is only output-order expectations in consumers that were implicitly relying on the earlier success line.

Focus areas for reviewers (optional)

• src/index.ts lifecycle ordering
• test/unit/index.test.ts event-order regression coverage

Checklist

• Error paths and exit codes considered where relevant
• Help text, completions, or docs updated if user-facing strings changed
• Squashed to a single commit
• No unrelated drive-by changes