v0.4.1

What changed

• Ordinary sync, including sync --dry-run, now detects pending recommended skill changes for existing user manifests.
• Show additions, updates, and removals as readable owner/repository entries with selected skill names instead of a JSON diff in the normal sync notice.
• Preserve existing manifest entries and locally differing sources; recommendation adoption remains explicit through sync --recommended-skills.
• Document the notice in README.md and docs/extending.md and add regression coverage for normal and dry-run sync.

Verification

• Behavioral suite: 221 tests run successfully, with 2 native-Windows-only skips.
• Tracked baseline validation passed; CLI version reports 0.4.1.
• Isolated sync preview confirmed readable recommendations without manifest or DotAi state changes.