docs: Phase 11 (partial) — fix cross-references after Phase 2 moves

Per Phase 1 audit at cowork/docs-overhaul-phase-1-audit-2026-05-04/.
Sweeps the highest-impact link surfaces affected by the Phase 2-7
mechanical moves and renames. Covers README.md (49 docs/ links) and
the most-trafficked docs/ files (compliance, getting-started, archive).

README.md fixes (49 link updates):
  - All single-doc references mapped from old to new paths:
    docs/quickstart.md → docs/getting-started/quickstart.md
    docs/architecture.md → docs/reference/architecture.md
    docs/connectors.md → docs/reference/connectors/index.md
    docs/acme-server.md → docs/reference/protocols/acme-server.md
    docs/{soc2,pci-dss,nist}.md → docs/compliance/{soc2,pci-dss,nist-sp-800-57}.md
    ... (full mapping in the sed pipeline)
  - 3 references to deleted features.md replaced with pointers to
    architecture.md + connectors/index.md.

docs/compliance/index.md (3 sibling renames):
  compliance-soc2.md     → soc2.md
  compliance-pci-dss.md  → pci-dss.md
  compliance-nist.md     → nist-sp-800-57.md

docs/compliance/pci-dss.md (3 external refs need ../):
  architecture.md  → ../reference/architecture.md
  connectors.md    → ../reference/connectors/index.md
  quickstart.md    → ../getting-started/quickstart.md

docs/getting-started/concepts.md (4 external refs):
  crl-ocsp.md      → ../reference/protocols/crl-ocsp.md
  architecture.md  → ../reference/architecture.md
  mcp.md           → ../reference/mcp.md
  openapi.md       → ../reference/api.md

docs/getting-started/quickstart.md (4 external refs + 1 sibling):
  tls.md           → ../operator/tls.md
  upgrade-to-tls.md → ../archive/upgrades/to-tls-v2.2.md
  architecture.md  → ../reference/architecture.md
  demo-advanced.md → advanced-demo.md (sibling rename)

docs/getting-started/examples.md (4 external refs):
  migrate-from-certbot.md         → ../migration/from-certbot.md
  migrate-from-acmesh.md          → ../migration/from-acmesh.md
  certctl-for-cert-manager-users.md → ../migration/cert-manager-coexistence.md
  connectors.md                   → ../reference/connectors/index.md

docs/archive/upgrades/to-tls-v2.2.md (3 external refs need ../../):
  tls.md           → ../../operator/tls.md
  quickstart.md    → ../../getting-started/quickstart.md
  test-env.md      → ../../contributor/test-environment.md

docs/archive/upgrades/to-v2-jwt-removal.md (2 external refs need ../../):
  architecture.md  → ../../reference/architecture.md
  tls.md           → ../../operator/tls.md

Verified all README.md docs/ links resolve to existing files. The only
remaining top-level link is testing-guide.md which still exists at the
top of docs/ (Phase 5 will prune it later).

Inter-doc broken links in deeper subdirectories (docs/reference/*,
docs/operator/*, docs/contributor/*) that don't appear in README's
direct surface area still need fixing in follow-up Phase 11 commits.
This commit handles the operator-facing entry points.

docs/compliance/pci-dss.md

@@ -817,9 +817,9 @@ Certctl v3 (Pro) adds paid features that strengthen PCI-DSS compliance posture:
 ## Questions?
 
 For additional guidance on certctl features and PCI-DSS mapping:
-- Review the [Architecture Guide](architecture.md) for system design.
-- Check [Connectors Documentation](connectors.md) for issuer/target/notifier capabilities.
-- Run the [Quick Start Guide](quickstart.md) to see features in action.
+- Review the [Architecture Guide](../reference/architecture.md) for system design.
+- Check [Connectors Documentation](../reference/connectors/index.md) for issuer/target/notifier capabilities.
+- Run the [Quick Start Guide](../getting-started/quickstart.md) to see features in action.
 - Consult your QSA for final compliance determination.
 
 **Last Updated**: March 24, 2026 (certctl v1.0 with M18b discovery and M19 audit logging)