Health checks are not wired to the state machine — ready?/0 reports true when Caddy is down

[gsmlg]

Problem

Caddy.ConfigManager.report_health_status/1 (lib/caddy/config_manager.ex:343) exists to drive the :synced → :degraded state transition, but nothing ever calls it.

Caddy.Server.External.do_health_check/1 (lib/caddy/server/external.ex:290) tracks Caddy status in its own GenServer state and emits telemetry, but never notifies ConfigManager.

Impact

• Caddy.ready?/0 returns true even when Caddy is unreachable
• The :degraded state defined in Caddy.State is unreachable in practice (dead code)

Fix

Call ConfigManager.report_health_status(:ok | :error) from Server.External.do_health_check/1 on status changes, so the application state machine reflects actual Caddy health.