fix(core): handle unsupported server error (#15164)

fix #15160
fix #15161
fix #15158
fix #15166


#### PR Dependency Tree


* **PR #15164** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added a “server version too old” message for self-hosted servers,
including the required upgrade version.
* Sign-in and OAuth-related preflight steps now verify server
compatibility before proceeding.
* **Bug Fixes**
* Improved error handling for missing/invalid server version responses
and schema/type mismatches, mapping them to the upgrade instruction.
* **Tests**
* Added coverage for server version guarding and the resulting
user-friendly error payload.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/base/error/def.ts

@@ -907,6 +907,14 @@ export const USER_FRIENDLY_ERRORS = {
     message: ({ clientVersion, requiredVersion }) =>
       `Unsupported client with version [${clientVersion}], required version is [${requiredVersion}].`,
   },
+  unsupported_server_version: {
+    type: 'action_forbidden',
+    args: {
+      requiredVersion: 'string',
+    },
+    message: ({ requiredVersion }) =>
+      `This AFFiNE server is too old for this client. Please upgrade the server to ${requiredVersion}.`,
+  },
 
   // Notification Errors
   notification_not_found: {