chore(openspec): archive all completed changes, sync 14 new specs to library

Archived 4 completed OpenSpec changes (2026-04-02):
- phase-3-enterprise (100/100 tasks) — 6 Phase 3 capabilities synced
- devops-documentation (48/48 tasks) — 3 new + 1 merged capability
- bedroom-developer-docs (33/33 tasks) — 4 new capabilities synced
- engineering-docs (superseded by 2026-03-29 archive) — no tasks

Main spec library grows from 21 → 35 capabilities (+14 new):
federation, multi-tenancy, oidc, soc2, w3c-dids, webhooks,
database, operations, system-overview, api-reference, core-concepts,
developer-guides, quick-start + deployment (merged additive requirements)

Active changes: 0 — project board is clear for Phase 4 planning.

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

openspec/changes/archive/2026-04-02-engineering-docs/specs/deployment-operations/spec.md

@@ -0,0 +1,28 @@
+## ADDED Requirements
+
+### Requirement: Deployment and operations guide
+The system SHALL include a document (`docs/engineering/10-deployment.md`) that explains how the application is built, deployed, and operated — covering Docker, Terraform, environment configuration, and monitoring.
+
+#### Scenario: Docker build and run documented
+- **WHEN** a new engineer reads 10-deployment.md
+- **THEN** they SHALL understand the multi-stage Dockerfile (builder stage compiles TypeScript, production stage runs compiled JS with node:18-alpine and non-root USER node), how to build the image, and how to run it with the required environment variables
+
+#### Scenario: Environment variables fully documented
+- **WHEN** a new engineer needs to configure the application
+- **THEN** the guide SHALL provide a complete table of all environment variables: name, purpose, required/optional, example value — covering database, Redis, JWT signing key, Vault, OPA, and rate limiting config
+
+#### Scenario: Database migrations documented
+- **WHEN** a new engineer needs to run or write migrations
+- **THEN** the guide SHALL explain: where migration files live (`migrations/`), the naming convention, how to run them (`npm run migrate`), and how to write a new migration following the existing pattern
+
+#### Scenario: Terraform multi-region deployment explained
+- **WHEN** a new engineer reads 10-deployment.md
+- **THEN** they SHALL understand the Terraform structure: what modules exist, what the three regions (US, EU, APAC) deploy, how to run `terraform plan` and `terraform apply`, and what AWS/GCP resources are provisioned
+
+#### Scenario: Prometheus metrics and Grafana explained
+- **WHEN** a new engineer reads 10-deployment.md
+- **THEN** they SHALL find: which endpoint exposes metrics (`/metrics`), the key metrics tracked, how to access the Grafana dashboard locally (port, login), and how to add a new metric counter or histogram to the API server
+
+#### Scenario: Operational runbook for common tasks
+- **WHEN** a new engineer is on-call or supporting operations
+- **THEN** the guide SHALL include a runbook covering: how to check application health, how to rotate the JWT signing key, how to revoke all tokens for a compromised agent, and how to read audit logs for an incident