test: close Linux platform command-coverage gaps from #1426

[thymikee]

Part of #1426.

The Linux platform manifest records these commands as known gaps because HEAD has no command-specific Linux evidence that meets the manifest contract:

• artifacts
• capabilities
• doctor
• shutdown
• logs
• events
• replay
• test
• install
• reinstall
• push
• batch
• diff
• record
• trace
• find
• swipe
• install-from-source

Follow-up work should add or identify executable Linux command evidence before changing the manifest rows. Keep the existing Linux replay smoke scope unchanged unless a separate platform-evidence decision explicitly expands it.