feat(tenancy): implement workspace isolation

src/langbot/templates/config.yaml

@@ -2,6 +2,12 @@ api:
     port: 5300
     webhook_prefix: 'http://127.0.0.1:5300'
     extra_webhook_prefix: ''
+    # Canonical browser origin when WebUI and API use different origins in
+    # development (for example http://localhost:3000). Production bundled UI
+    # may leave this empty when webhook_prefix already has the browser origin.
+    # OAuth redirects trust only these server-side values, never request Host
+    # or Origin headers.
+    webui_url: ''
     # Global API key for the HTTP service API and the MCP server. When set to a
     # non-empty string, this key is accepted anywhere a web-UI-created API key is
     # accepted (X-API-Key header or "Authorization: Bearer <key>"), WITHOUT any
@@ -142,6 +148,8 @@ box:
     enabled: true
     backend: 'local'  # 'local' (Docker/nsjail), 'docker', 'nsjail', or 'e2b'. Can be written via BOX__BACKEND.
     runtime:
+        # External WebSocket runtimes also require LANGBOT_BOX_CONTROL_TOKEN in
+        # both LangBot and Box. Keep the shared secret out of this config file.
         endpoint: ''  # External Box Runtime base URL, e.g. 'ws://127.0.0.1:5410'. Leave empty for local auto-managed runtime.
     local:
         profile: 'default'