deva doctor: preflight and diagnostics

[lroolle]

Description

Half the auth/mount issue queue is users lacking a diagnostic. deva doctor checks the environment and prints pass/warn/fail lines.

Type

• New feature

Details

Checks: docker reachable; image present and tag vs versions.env expectation; per-agent auth state (config dirs exist, credential files readable, api-key env set); mount shape sanity; proxy env that breaks builds (HTTP_PROXY on docker builds); deprecated layouts (feeds #518 migration). Read-only, exit non-zero on fail, plain ascii output.

Related Files

• deva.sh
• scripts/test-status-helpers.sh

Test Plan

• doctor passes on healthy setup
• each failing check produces one actionable line and non-zero exit
• no writes anywhere (hermetic run under scratch XDG)