Feat v0.6.1-v0.6.2: backup/restore, docs surface, dynamic OpenAPI

v0.6.1 — Backup tooling (.swb ZIP export/import), admin backup section,
docs surface with markdown rendering, 5 reference docs, 6 handler tests.

v0.6.2 — Dark mode contrast fixes, topbar nav, 📖 docs icon, dynamic
OpenAPI spec with extension route merging, docs outline sidebar,
scroll/routing fixes; 7 new tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,40 @@
 
 All notable changes to Switchboard Core are documented here.
 
+## v0.6.1 — Backup/Restore + Documentation
+
+Operational tooling for data safety and extension authoring.
+
+### Added
+
+- **Backup/Restore**: Full-instance backup as `.swb` ZIP archive containing
+  core tables (JSONL), ext_data tables, and package assets. Stream to client
+  or save server-side. Restore wipes and rebuilds from archive. Dialect-neutral
+  (works across SQLite and Postgres).
+- **Admin backup section**: New "Backup" tab under `/admin` with create,
+  download, delete, and restore operations. Destructive restore requires
+  confirmation dialog.
+- **Documentation surface**: Builtin surface at `/docs` with sidebar navigation
+  and client-side markdown rendering. Ships with 5 documents: Getting Started,
+  Extension Guide, API Reference, Deployment, Package Format.
+- **Docs API**: `GET /api/v1/docs` lists available documents, `GET /api/v1/docs/:name`
+  returns raw markdown content. Authenticated (all users).
+- **Tests**: 6 backup handler tests + E2E script (`ci/e2e-backup-test.sh`).
+
+### API
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/v1/admin/backup` | POST | Create backup (stream or `?store=true`) |
+| `/api/v1/admin/backups` | GET | List server-side backups |
+| `/api/v1/admin/backups/:name` | GET | Download backup |
+| `/api/v1/admin/backups/:name` | DELETE | Delete backup |
+| `/api/v1/admin/restore` | POST | Restore from `.swb` upload |
+| `/api/v1/docs` | GET | List documentation |
+| `/api/v1/docs/:name` | GET | Get document content |
+
+---
+
 ## v0.6.0 — Cluster Registry + HA
 
 MVP convergence point. PG-backed cluster registry for horizontal scaling —