docs: commit all Phase 6 documentation updates and OpenSpec archives

- devops docs: 8 files updated for Phase 6 state; field-trial.md added (946-line runbook)
- developer docs: api-reference (50+ endpoints), quick-start, 5 existing guides updated, 5 new guides added
- engineering docs: all 12 files updated (services, architecture, SDK guide, testing, overview)
- OpenSpec archives: phase-7-devops-field-trial, developer-docs-phase6-update, engineering-docs-phase6-update
- VALIDATOR.md + scripts/start-validator.sh: V&V Architect tooling added
- .gitignore: exclude session artifacts, build artifacts, and agent workspaces

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

openspec/changes/archive/phase-7-devops-field-trial/proposal.md

@@ -0,0 +1,35 @@
+# OpenSpec Proposal — phase-7-devops-field-trial
+
+**Status:** Approved  
+**Proposed:** 2026-04-04  
+**Approved by:** CEO  
+
+## Problem Statement
+
+The existing `docs/devops/` was written during Phase 2 (archived 2026-04-02). Phases 3–6 added
+substantial new infrastructure — 14 new DB migrations, Phase 6 feature flags, Stripe integration,
+new services (Analytics, Tier, Compliance, A2A), and the Next.js portal — none of which are
+reflected in the current DevOps documentation.
+
+Additionally, the team is preparing for in-house Docker Compose field trials and has no
+deployment execution guide.
+
+## Proposed Solution
+
+**WS1 — Update Existing DevOps Docs**
+Audit and update all files in `docs/devops/` to reflect the current Phase 6 state of the
+codebase. Every env var, migration, service, and port must be accurate.
+
+**WS2 — New In-House Field Trial Guide**
+Create `docs/devops/field-trial.md` — a step-by-step execution playbook covering:
+- Phase A: Stack startup verification
+- Phase B: Core product end-to-end journeys
+- Phase C: Security guardrails and tenant isolation
+- Phase D: Next.js portal verification
+- Phase E: AGNTCY conformance suite against live environment
+- Phase F: Performance baseline
+
+## CEO Approval
+
+Approved 2026-04-04 per CEO directive: "YES Approved per CTO recommendations — implement your
+plan per Openspec Protocol"