Raise test line coverage from 47% to 70%+

[nikhil2611]

Epic

Part of Crawl Track backlog epic.

Background

Ex2 (Coverage Improvement) raised coverage incrementally. Current line coverage is 47.26% (3558/7528 lines). The advisory CI job (Ex10) surfaces this on every push.

Code Paths

• lib/chef/knife/*.rb — most subcommands have minimal or no unit tests
• High-value targets: lib/chef/knife/bootstrap.rb, lib/chef/knife/search.rb, lib/chef/knife/ssh.rb

Acceptance Criteria

• Line coverage ≥ 70% as reported by SimpleCov in CI job summary
• New specs added under spec/unit/knife/ for at least 5 under-tested commands
• No existing tests broken
• Coverage advisory job shows ✅ (green) instead of ⚠️

Dependencies

• Depends on: CI advisory job (Ex10) already merged
• Blocks: nothing

Estimated Size

Large — multiple PRs recommended, one per command group