Read mounted secret files (Claude OAuth, OpenCode auth.json) and env
vars on boot, register them as credentials, fetch available models
from provider APIs, and create default agent configs for each viable
runtime+provider+model combination.
Strip all seed/mock data (fake tasks, models, usage entries, agent configs)
so the dashboard starts clean and populates from real API state. Add
/api/agents/health endpoint that validates each agent's provider credentials
and CLI availability.
