Chore: trim roadmap head, add v0.6.3–v0.6.6 from audit, update changelog

- ROADMAP.md: replace Phase 0 + v0.2.x–v0.5.x detail with a one-paragraph
  summary (full history preserved in CHANGELOG.md); add v0.6.3–v0.6.6
  pre-fork hardening track from the v0.6.2 brutal audit; add three new
  Design Decisions Log entries (builtin package rationale, cluster
  dashboard retirement, block renderers decoupled from chat)
- CHANGELOG.md: add v0.6.2 entry (dark mode, routing/scrolling fixes,
  dynamic OpenAPI, Postgres test fix)

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

CHANGELOG.md

@@ -2,6 +2,49 @@
 
 All notable changes to Switchboard Core are documented here.
 
+## v0.6.2 — Docs Polish + Dynamic OpenAPI
+
+Docs surface polish and dynamic OpenAPI spec with extension route merging.
+
+### Added
+
+- **Dynamic OpenAPI spec**: `GET /api/docs/openapi.json` builds a merged
+  spec at request time — kernel endpoints + auto-generated stubs for every
+  extension `api_routes` entry. Extensions may optionally declare `api_schema`
+  in `manifest.json` for richer path items (params, body, response examples).
+- **`api_schema` manifest field**: Optional array in `manifest.json`. Malformed
+  entries are logged and skipped — never blocks extension loading.
+- **Tests**: 7 new handler tests (zero extensions, stubs, rich schema,
+  multi-extension, malformed schema, disabled exclusion, required fields).
+
+### Fixed
+
+- **Dark mode contrast**: Replaced all hardcoded light-mode fallbacks in docs
+  CSS with theme-aware CSS variables. Tables, code blocks, nav items, and
+  headings now readable in dark mode.
+- **Docs loading state**: Replaced borrowed `settings-placeholder` animation
+  with docs-specific pulse skeleton. Added error state with retry button.
+- **Docs routing**: Default route (`/docs`) now redirects to
+  `/docs/GETTING-STARTED` instead of the blank `/:section` placeholder.
+- **Docs scrolling**: Content area now scrolls correctly — full document
+  visible without text overflowing viewport.
+- **Docs icon**: Changed from 🧩 to 📖 in the user menu.
+- **Docs duplicate menu entry**: Docs was appearing twice (once from surfaces
+  API, once from hardcoded items). Added `'docs'` to `CORE_IDS` filter.
+- **Swagger UI**: Updated to point at dynamic `/api/docs/openapi.json`
+  endpoint. Static YAML preserved for backward compatibility.
+- **OpenAPI tests on Postgres**: `openapiTestStores()` was hardcoded to
+  `sqlite.NewStores()` — caused `pq: syntax error at or near ","` in CI.
+  Now uses `database.IsSQLite()` check like all other handler tests.
+
+### API
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/docs/openapi.json` | GET | Dynamic merged OpenAPI 3.0 spec |
+
+---
+
 ## v0.6.1 — Backup/Restore + Documentation
 
 Operational tooling for data safety and extension authoring.