Agent Skills: health-check

Diagnose the po Pushover plugin and check remaining monthly quota. Runs a full self-test (credential resolution via 1Password/Keychain, /users/validate.json, quota, expected custom sounds present, deps bun/uv/Chrome for Testing with system Chrome as the fallback, audit log) and reports message quota remaining. Use when the user asks if Pushover is working, why a notification failed, how many messages are left, or wants a health/diagnostic check. TRIGGERS - pushover health, po doctor, pushover not working, pushover quota, messages left, diagnose pushover.