docs: README + concepts + features reflect CRL/OCSP responder bundle

Audit pass against cowork/crl-ocsp-responder-prompt.md found three
operator-facing docs still describing the pre-bundle CRL/OCSP surface
(GET-only OCSP, CA-key-direct signing, no scheduler-driven cache). Each
claim updated below was ground-truthed against repo HEAD before edit.

README.md
  * Standards & Revocation table — CRL row now mentions
    scheduler-pre-generated cache (CERTCTL_CRL_GENERATION_INTERVAL,
    crl_cache table); OCSP row mentions GET + POST forms, dedicated
    responder cert per RFC 6960 §2.6, id-pkix-ocsp-nocheck per
    §4.2.2.2.1, 7d auto-rotation grace.
  * Revocation paragraph — corrected the 'Embedded OCSP responder'
    one-liner to call out the dedicated-responder-cert design (the CA
    private key is never used directly for OCSP signing, which is the
    load-bearing security property for the future PKCS#11/HSM driver
    path) and added the link to the relying-party guide.

docs/concepts.md
  * CRL paragraph — added the scheduler pre-generation + singleflight
    coalescing detail. Kept the existing 24h validity claim (verified
    against internal/connector/issuer/local/local.go:956 — 'NextUpdate:
    now.Add(24 * time.Hour)').
  * OCSP paragraph — corrected the description so it covers both GET
    and POST forms (POST per RFC 6960 §A.1.1 is what production
    clients use: Firefox, OpenSSL s_client -status, cert-manager,
    Intune); added the dedicated-responder-cert + nocheck-extension +
    auto-rotation explanation; cross-link to docs/crl-ocsp.md.

docs/features.md
  * Revocation Infrastructure section — CRL Endpoint, OCSP Responder,
    new Admin Cache Observability subsection, new GUI Revocation
    Endpoints Panel subsection. Corrected the previously-wrong 'Signs
    with the issuing CA key' OCSP claim — the bundle's load-bearing
    security improvement is exactly that the CA key is NOT used
    directly. Cross-link to crl-ocsp.md.
  * Local CA env vars table — added all four new
    CERTCTL_CRL_GENERATION_INTERVAL / CERTCTL_OCSP_RESPONDER_KEY_DIR
    (with the prod 'MUST set' callout) / _ROTATION_GRACE / _VALIDITY
    rows. Closes the G-3 'env var defined in Go but never documented'
    drift that broke CI on commit fc3c7ad.
  * Migrations table — added 000019_crl_cache and 000020_ocsp_responder
    rows so the table reflects the bundle's persisted surface area;
    also clarified the table is illustrative + pointed readers at
    'ls migrations/*.up.sql' for the full sequence (the table had
    drifted behind reality at 000010 even before this bundle).

docs/architecture.md was already updated in commit b4334ed with the
same content scope, so no further architecture edits.

Verification:
  * Local G-3 set difference: empty (Go-defined ∖ docs-mentioned for
    CRL/OCSP env vars).
  * 24h CRL validity claim verified against local.go:956 NextUpdate.
  * Migration numbers verified against 'ls migrations/000019* 000020*'.
  * id-pkix-ocsp-nocheck OID verified against
    internal/connector/issuer/local/ocsp_responder.go:60.

README.md

@@ -115,8 +115,8 @@ gantt
 
 | Capability | Standard | Notes |
 |------------|----------|-------|
-| DER-encoded X.509 CRL | RFC 5280 | Per-issuer, signed by issuing CA, 24h validity |
-| Embedded OCSP responder | RFC 6960 | Good/revoked/unknown status per issuer |
+| DER-encoded X.509 CRL | RFC 5280 | Per-issuer, signed by issuing CA, 24h validity. Pre-generated by the scheduler (`CERTCTL_CRL_GENERATION_INTERVAL`, default 1h) and cached in `crl_cache` so HTTP fetches do not rebuild per request. |
+| Embedded OCSP responder | RFC 6960 | GET + POST forms (`POST /.well-known/pki/ocsp/{issuer_id}` per §A.1.1). Signed by a per-issuer dedicated OCSP responder cert (RFC 6960 §2.6) carrying `id-pkix-ocsp-nocheck` (§4.2.2.2.1) — the CA private key is never used directly for OCSP signing. Responder cert auto-rotates within 7d of expiry. |
 | S/MIME certificates | RFC 8551 | Email protection EKU, adaptive KeyUsage flags |
 | Certificate export | — | PEM (JSON/file) and PKCS#12 formats |
 | ACME DNS-PERSIST-01 | IETF draft | Standing validation record, no per-renewal DNS updates |
@@ -175,7 +175,7 @@ Built for **platform engineering and DevOps teams** managing 10–500+ certifica
 
 **Enrollment protocols.** EST server (RFC 7030) for device and WiFi enrollment. SCEP server (RFC 8894) for MDM platforms and network devices. S/MIME issuance with email protection EKU.
 
-**Revocation.** Single and bulk revocation (by profile, owner, agent, or issuer). DER-encoded X.509 CRL per issuer, signed by the issuing CA. Embedded OCSP responder. RFC 5280 reason codes. Short-lived certs (TTL < 1 hour) are exempt — expiry is sufficient revocation.
+**Revocation.** Single and bulk revocation (by profile, owner, agent, or issuer). RFC 5280 reason codes. Production-grade revocation status surface for relying parties: DER-encoded X.509 CRL per issuer, scheduler-pre-generated and cached so HTTP fetches do not rebuild per request; embedded OCSP responder serving both GET and POST forms (RFC 6960 §A.1.1) with responses signed by a per-issuer dedicated OCSP responder cert (RFC 6960 §2.6, `id-pkix-ocsp-nocheck` per §4.2.2.2.1) — the CA private key is never used directly for OCSP signing. Both endpoints live unauthenticated under `/.well-known/pki/` per RFC 8615. Short-lived certs (TTL < 1 hour) are exempt — expiry is sufficient revocation. See [docs/crl-ocsp.md](docs/crl-ocsp.md) for the relying-party integration guide.
 
 **Audit and observability.** Immutable append-only audit trail records every lifecycle action, every API call, and every approval decision. Prometheus metrics endpoint. Scheduled certificate digest emails. Continuous endpoint health monitoring with state machine transitions and real-time alerts.