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- engineering-docs (superseded by 2026-03-29 archive) — no tasks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-devops-documentation/specs/system-overview/spec.md

@@ -0,0 +1,10 @@
+## ADDED Requirements
+
+### Requirement: System overview exists at docs/devops/README.md
+The system SHALL provide a `docs/devops/README.md` that serves as the entry point for DevOps engineers, including an index of all DevOps docs and a brief system overview.
+
+### Requirement: Architecture doc exists at docs/devops/architecture.md
+The system SHALL provide `docs/devops/architecture.md` documenting all components (Express server, PostgreSQL, Redis), their roles, ports, and data flow.
+
+### Requirement: Environment variable reference exists at docs/devops/environment-variables.md
+The system SHALL provide `docs/devops/environment-variables.md` documenting every environment variable with name, type, required/optional, default, and example value.