Preserve version specifier prefixes when applying fixes

Summary

• Preserve user's original semver behavior when applying fixes (^15.3.0 → ^15.3.7)
• Add getVersionPrefix() and applyVersionPrefix() utilities
• Display prefixed version in CLI output

Test plan

• Unit tests for prefix extraction and application
• End-to-end tests verifying prefix flows through analysis → fix computation
• All 372 tests passing