Release v0.3.6

MantisBase v0.3.6

This release standardizes the REST API surface, scopes authentication to
individual entities, and moves admin management into a dedicated namespace.
It includes breaking API changes — see the migration notes below.

Blog post available here

🚨 Breaking Changes

• Auth endpoints are now per-entity. The target entity moved from the
  request body into the URL path:
  • POST /api/v1/auth/login → POST /api/v1/auth/<entity>/login
  • POST /api/v1/auth/refresh → POST /api/v1/auth/<entity>/refresh
  • POST /api/v1/auth/logout → POST /api/v1/auth/<entity>/logout
  • The "entity" field is no longer read from the login body.
• Admin auth & setup moved out of /auth into the system namespace:
  • POST /api/v1/auth/setup/admin → POST /api/v1/sys/admins/setup
  • Admin login/refresh/logout now live under /api/v1/sys/admins/.
• File serving path is now versioned:
  GET /api/files/<entity>/<filename> → GET /api/v1/files/<entity>/<filename>
• Auth login response is now wrapped in the standard envelope
  ({ "status", "data", "error" }) instead of returning the token/user at
  the top level.

✨ Features & Improvements

• Standardized API namespaces — all endpoints grouped consistently under
  /api/v1/: auth/<entity>, entities, schemas, files, health,
  sys/logs, sys/admins, sys/settings, realtime.
• Full admin CRUD under /api/v1/sys/admins/ (list, get, create, update,
  delete) alongside admin auth and initial setup.
• Settings endpoints documented: GET|PATCH /api/v1/sys/settings/config.
• Health check moved back out of /sys to /api/v1/health.
• Auth routes now validate the target entity (must be an auth-type,
  non-system, API-enabled entity) and return 404 otherwise.

🧹 Internal / Refactors

• Centralized entity CRUD routes into unified generic handlers to reduce
  memory usage (no longer one handler set per entity).
• Decoupled schema route handlers from the schema object.
• Pulled in WolfSSL updates; disabled a WolfSSL string-overflow warning.
• Updated bundled submodules: json, jwt-cpp, spdlog, wolfssl,
  mb-admin.
• Fixed clashing build targets for the zstd target.

📖 Docs

• Rewrote the Authentication API guide, API reference, and Quick Start for the
  new per-entity auth and /api/v1/sys/* layout.

Full Changelog: v0.3.5...v0.3.6