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/service/testutil_test.go

@@ -716,6 +716,17 @@ func (m *mockIssuerConnector) GetCACertPEM(ctx context.Context) (string, error)
 	return "-----BEGIN CERTIFICATE-----\nmock-ca-cert\n-----END CERTIFICATE-----", nil
 }
 
+func (m *mockIssuerConnector) GetRenewalInfo(ctx context.Context, certPEM string) (*RenewalInfoResult, error) {
+	if m.Err != nil {
+		return nil, m.Err
+	}
+	now := time.Now()
+	return &RenewalInfoResult{
+		SuggestedWindowStart: now,
+		SuggestedWindowEnd:   now.Add(7 * 24 * time.Hour),
+	}, nil
+}
+
 // Constructor functions for mocks
 
 func newMockCertificateRepository() *mockCertRepo {