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>

docs/features.md

@@ -1469,8 +1469,8 @@ Each guide includes an evidence summary table mapping specific criteria to certc
 | **Bulk revocation** | ✗ | ✓ | Planned V3 (paid) |
 | **Certificate health scores** | ✗ | ✓ | Planned V3 |
 | **Compliance scoring** | ✗ | ✓ | Planned V3 |
-| **DigiCert issuer** | ✗ | ✓ | Planned V2.1 (free) |
-| **Vault PKI issuer** | ✗ | ✓ | Planned V2.1 (free) |
+| **DigiCert issuer** | ✗ | ✓ | Implemented (Beta) |
+| **Vault PKI issuer** | ✗ | ✓ | Implemented (Beta) |
 
 ---