fix(whatsapp): repair partial bridge installs

[LeonSGP43]

Summary

• repair WhatsApp bridge setup when an interrupted npm install leaves a partial node_modules/
• reuse the package-lock freshness check so stale bridge installs are repaired automatically
• add regression tests for partial, stale, and healthy bridge dependency states

Testing

• pytest -o addopts='' tests/hermes_cli/test_whatsapp_setup.py tests/hermes_cli/test_tui_npm_install.py

Closes #13413

[alt-glitch]

Likely duplicate of #13499 — both fix interrupted WhatsApp bridge installs from #13413 with the same approach (checking dependency health, not just directory existence).

[alt-glitch]

Likely duplicate of #13499 — both fix interrupted WhatsApp bridge installs from #13413 with the same approach (checking dependency health, not just directory existence).