feat: frontend audit fixes, README accuracy pass, doc updates

Frontend audit (10 categories): lifecycle fields in types, new API
functions (CRL, OCSP, deployments, updateIssuer/Target, getPolicy),
issuer/owner/profile filters on CertificatesPage, last_renewal_at
column, error_message column on JobsPage, full crypto policy UI on
ProfilesPage (key algorithms, EKUs, SAN patterns), key info + CA
badge on DiscoveryPage, edit modal on TargetDetailPage, tags field
on certificate creation, darwin→macOS mapping on AgentFleetPage.
211 Vitest tests passing.

README accuracy: test counts (1300+ Go, 211 frontend), page count
(24), demo data (32 certs, 7 issuers, 180 days), endpoint count
(97), MCP tools (80), CLI subcommands (10), moved shipped items
out of "Coming in v2.1.0".

Docs: architecture.md diagrams updated (Vault PKI, DigiCert,
Traefik, Caddy added), features.md Vault/DigiCert status updated.
Version bumped to v2.0.20. cli binary removed from git tracking.
Testing guide Part 41 added (12 auto + 9 manual tests).

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

web/src/pages/JobsPage.tsx

@@ -136,6 +136,15 @@ export default function JobsPage() {
       label: 'Attempts',
       render: (j) => <span className="text-ink-muted">{j.attempts}/{j.max_attempts}</span>,
     },
+    {
+      key: 'error',
+      label: 'Error',
+      render: (j) => j.status === 'Failed' && j.error_message ? (
+        <span className="text-xs text-red-600 truncate max-w-[200px] inline-block" title={j.error_message}>
+          {j.error_message.length > 80 ? j.error_message.substring(0, 80) + '...' : j.error_message}
+        </span>
+      ) : <span className="text-xs text-ink-faint">—</span>,
+    },
     { key: 'scheduled', label: 'Scheduled', render: (j) => <span className="text-xs text-ink-muted">{formatDateTime(j.scheduled_at)}</span> },
     { key: 'completed', label: 'Completed', render: (j) => <span className="text-xs text-ink-muted">{formatDateTime(j.completed_at)}</span> },
     {