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/DiscoveryPage.tsx

@@ -197,6 +197,18 @@ export default function DiscoveryPage() {
       label: 'Expiry',
       render: (c) => <span className="text-xs">{formatExpiry(c.not_after)}</span>,
     },
+    {
+      key: 'key_info',
+      label: 'Key',
+      render: (c) => (
+        <div className="flex items-center gap-1">
+          <span className="text-xs text-ink-muted">{c.key_algorithm}{c.key_size ? ` ${c.key_size}` : ''}</span>
+          {c.is_ca && (
+            <span className="text-[10px] px-1.5 py-0.5 rounded bg-purple-100 text-purple-700 font-medium">CA</span>
+          )}
+        </div>
+      ),
+    },
     {
       key: 'fingerprint',
       label: 'Fingerprint',