[codex] Add VibeStack Doctor troubleshooting

[dankritz]

Summary

• Add VibeStack Doctor: a deterministic app troubleshooting packet at GET /api/v1/apps/:id/doctor with root-cause category, evidence, health-check result, Postgres hints, retry guidance, and a coding-agent fix prompt.
• Add optional OpenRouter enrichment using openai/gpt-5.5, with the API key encrypted in platform_settings and returned to the UI only as configured/status flags.
• Add an app-detail Doctor panel with copyable fix prompt, Settings controls for OpenRouter, deploy-helper Doctor fetches after failed deployments, and skill/API docs updates.
• Bump VibeStack from 0.2.2-alpha.0 to 0.2.3-alpha.0 and vibestackRelease from 0.2c to 0.2d.

Validation

• npm run typecheck
• npm test
• python3 skills/deploy-to-vibestack/scripts/vibestack_deploy_test.py
• npm run build
• npm run lint

Notes

Browser visual smoke was attempted against the local Vite server, but the in-app browser blocked localhost navigation with net::ERR_BLOCKED_BY_CLIENT; build/typecheck/tests covered the UI compile path.