fix: end-to-end certificate lifecycle bugs + integration test environment

Fixes 12 production bugs preventing the full issuance→deployment flow
from working with ACME (Pebble/Let's Encrypt) and step-ca issuers:

ACME connector (acme.go):
- Save orderURI before WaitOrder overwrites it (Go crypto/acme bug)
- Add CreateOrderCert fallback via WaitOrder+FetchCert
- Remove defer-reset in ValidateConfig that caused nil pointer panic
- Add Insecure TLS option for self-signed ACME servers (Pebble)

step-ca connector (stepca.go, jwe.go):
- Real JWE provisioner key loading + decryption (was using ephemeral keys)
- Fix JWT audience (/1.0/sign), sha claim (key fingerprint), kid header
- Custom root CA trust via RootCertPath config
- Remove hardcoded 90-day validity default (let step-ca decide)

NGINX target connector (nginx.go):
- Use sh -c for validate/reload commands (shell interpretation)
- Use filepath.Dir instead of fragile string slicing
- Add private key file writing (agent-mode keys were never deployed)
- Make chain_path write conditional

Server/service layer:
- TriggerRenewalWithActor now creates actual Job records (was no-op)
- createDeploymentJobs falls back to DB query when cert.TargetIDs empty
- ProcessPendingJobs skips agent-routed deployment jobs
- Agent cert pickup path parsing: len(parts)<4 → len(parts)<3
- Health/ready/auth-info endpoints bypass auth middleware
- Write timeout 15s→120s for ACME issuance
- Cert fingerprint computed on CSR submission

Integration test environment (deploy/test/):
- 10-phase test script covering Local CA, ACME, step-ca, revocation,
  discovery, renewal, and API spot checks
- Docker Compose with 7 containers (server, agent, postgres, nginx,
  pebble, challtestsrv, step-ca) on isolated network
- TLS verification checks SAN (not just Subject CN) for modern CA compat

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

internal/service/agent.go

@@ -178,14 +178,15 @@ func (s *AgentService) SubmitCSR(ctx context.Context, agentID string, certID str
 			}
 
 			version := &domain.CertificateVersion{
-				ID:            generateID("certver"),
-				CertificateID: certID,
-				SerialNumber:  result.Serial,
-				NotBefore:     result.NotBefore,
-				NotAfter:      result.NotAfter,
-				PEMChain:      result.CertPEM + "\n" + result.ChainPEM,
-				CSRPEM:        string(csrPEM),
-				CreatedAt:     time.Now(),
+				ID:                generateID("certver"),
+				CertificateID:     certID,
+				SerialNumber:      result.Serial,
+				NotBefore:         result.NotBefore,
+				NotAfter:          result.NotAfter,
+				FingerprintSHA256: computeCertFingerprint(result.CertPEM),
+				PEMChain:          result.CertPEM + "\n" + result.ChainPEM,
+				CSRPEM:            string(csrPEM),
+				CreatedAt:         time.Now(),
 			}
 
 			if err := s.certRepo.CreateVersion(ctx, version); err != nil {