Update dependencies and improve documentation

Bumped several production and dev dependencies to their latest versions (apollo/server, graphql, mongoose, react, eslint, etc.) and removed the unused rxjs dependency. Added demo mode documentation to Options.md and added the missing import-x/no-named-as-default ESLint rule to AGENTS.md.

Author: electerious

AGENTS.md

@@ -203,6 +203,7 @@ Base config: `@electerious/eslint-config`
 Disabled rules for this project:
 
 - `import-x/dynamic-import-chunkname`
+- `import-x/no-named-as-default`
 - `unicorn/filename-case`
 - `unicorn/consistent-function-scoping`
 - `unicorn/no-await-expression-member`

docs/Options.md

@@ -72,6 +72,14 @@ Set the environment to `development` to see additional details in the console an
 NODE_ENV=development
 ```
 
+## Demo mode
+
+Set to `true` to enable demo mode. In demo mode, all mutations (creating, updating, deleting) are blocked, and the GraphQL Playground is enabled.
+
+```
+ACKEE_DEMO=true
+```
+
 ## CORS headers
 
 Quick solution for setting [CORS headers](CORS%20headers.md) instead of using a [reverse proxy](SSL%20and%20HTTPS.md). This is helpful if you are running Ackee on a platform that handles SSL for you.