feat(cert): dial the TLS terminator directly so cert-expiry works from the container

checkCertExpiry now accepts a `dial` address and sets ServerName to the
hostname — it connects to the terminator's IP while SNI/cert-read use the
hostname. The scheduler container has no mesh interface and the host resolver
doesn't know the split-horizon zone, so *.hubris.network can't be dialed by
name from there; dialing Caddy's lab IP (reachable on the LAN) makes the probe
work. The builder passes through a cert entity's `dial` attribute.

Re-seed the 20 *.hubris.network certificate entities with dial=192.168.8.175
(Caddy) and uses-certificate edges; cert-expiry monitoring now has real data.

internal/checkdefaults/defaults.go

@@ -249,17 +249,26 @@ func buildKind(kind string, t Target, attrs map[string]any, host, user string, p
 		}}, ""
 
 	case KindCertExpiry:
-		// The host to TLS-dial for the cert. Prefer an explicit `hostname`
-		// attribute, then `cn`, then a dotted name (a certificate's name is
-		// its CN/SAN). Hourly: expiry changes once a day, but a renewal or a
-		// mis-issued cert is worth noticing within the hour.
+		// The host whose cert to read (SNI / cert CN). Prefer an explicit
+		// `hostname` attribute, then `cn`, then a dotted name. Hourly: expiry
+		// changes once a day, but a renewal or mis-issued cert is worth
+		// noticing within the hour.
 		host := certHost(t, attrs)
 		if host == "" {
 			return nil, "no hostname / cn / dotted name to dial for the cert"
 		}
+		// `dial` is the TLS terminator's address to connect to (Caddy's lab
+		// IP), used when the hostname doesn't resolve/reach from the scheduler.
+		// Without it the probe can't reach *.hubris.network from a container
+		// with no mesh / split-horizon DNS.
+		dial, _ := attrs["dial"].(string)
+		config := map[string]any{"host": host, "warn_days": 30, "crit_days": 7}
+		if dial != "" {
+			config["dial"] = dial
+		}
 		return []checkDef{{
 			kind:     "cert-expiry",
-			config:   map[string]any{"host": host, "warn_days": 30, "crit_days": 7},
+			config:   config,
 			interval: 3600,
 		}}, ""
 	}

internal/scheduler/scheduler.go

@@ -536,6 +536,12 @@ func checkDisk(ctx context.Context, cd sqlcgen.ListEnabledCheckDefsRow) checkRes
 func checkCertExpiry(ctx context.Context, cd sqlcgen.ListEnabledCheckDefsRow) checkResult {
 	cfg := struct {
 		Host     string `json:"host"`
+		// Dial is an optional explicit dial address (the TLS terminator's IP)
+		// for when the hostname doesn't resolve/reach from the scheduler — the
+		// container has no mesh interface and the host resolver doesn't know
+		// the split-horizon zone, so *.hubris.network dials Caddy's lab IP
+		// directly while SNI/cert-read still uses Host.
+		Dial     string `json:"dial"`
 		Port     int    `json:"port"`
 		WarnDays int    `json:"warn_days"`
 		CritDays int    `json:"crit_days"`
@@ -556,9 +562,13 @@ func checkCertExpiry(ctx context.Context, cd sqlcgen.ListEnabledCheckDefsRow) ch
 		timeout = 30 * time.Second
 	}
 
-	addr := net.JoinHostPort(cfg.Host, fmt.Sprintf("%d", cfg.Port))
+	dialHost := cfg.Host
+	if cfg.Dial != "" {
+		dialHost = cfg.Dial
+	}
+	addr := net.JoinHostPort(dialHost, fmt.Sprintf("%d", cfg.Port))
 
-	d := tls.Dialer{Config: &tls.Config{InsecureSkipVerify: true}}
+	d := tls.Dialer{Config: &tls.Config{InsecureSkipVerify: true, ServerName: cfg.Host}}
 	conn, err := d.DialContext(ctx, "tcp", addr)
 	if err != nil {
 		return checkResult{