feat(m28+m29+m30): ACME ARI, email digest, and Helm chart

M28: ACME Renewal Information (RFC 9702) — CA-directed renewal timing
with cert ID computation, directory endpoint discovery, graceful
degradation for non-ARI CAs. 19 tests.

M29: Email notifier wiring + scheduled certificate digest — SMTP
connector bridged to service layer via NotifierAdapter, DigestService
with HTML email template, 7th scheduler loop (24h), digest preview/send
API endpoints and GUI card. 21 tests.

M30: Production-ready Helm chart — server Deployment, PostgreSQL
StatefulSet, agent DaemonSet, ConfigMaps, Secrets, Ingress, security
contexts, health probes, example values for dev/prod/ACME scenarios.

Also: OpenAPI spec updates, MCP tool additions, CI helm-lint job,
documentation updates across 5 doc files and README.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/connector/notifier/email/adapter.go

@@ -0,0 +1,42 @@
+package email
+
+import (
+	"context"
+	"fmt"
+)
+
+// NotifierAdapter bridges the email.Connector (notifier.Connector interface) to the
+// service.Notifier interface used by the notification registry. This adapter allows
+// the existing email SMTP connector to be registered alongside Slack, Teams, etc.
+type NotifierAdapter struct {
+	connector *Connector
+}
+
+// NewNotifierAdapter wraps an email.Connector to implement service.Notifier.
+func NewNotifierAdapter(c *Connector) *NotifierAdapter {
+	return &NotifierAdapter{connector: c}
+}
+
+// Channel returns the notification channel identifier.
+func (a *NotifierAdapter) Channel() string {
+	return "Email"
+}
+
+// Send delivers a notification via SMTP email.
+// The recipient is the email address, subject is used as the email subject,
+// and body is the email body content.
+func (a *NotifierAdapter) Send(ctx context.Context, recipient string, subject string, body string) error {
+	if recipient == "" {
+		return fmt.Errorf("email: recipient address is required")
+	}
+	return a.connector.sendEmail(ctx, recipient, subject, body)
+}
+
+// SendHTML delivers an HTML email notification via SMTP.
+// Used by the digest service for rich HTML digest emails.
+func (a *NotifierAdapter) SendHTML(ctx context.Context, recipient string, subject string, htmlBody string) error {
+	if recipient == "" {
+		return fmt.Errorf("email: recipient address is required")
+	}
+	return a.connector.sendHTMLEmail(ctx, recipient, subject, htmlBody)
+}