fix(admin): prevent fallback to 'latest' string when dockerhub tags c… (#22885)

Fixes #22849 

### What changed?
When the `AdminPanelVersionService` hits a DockerHub API error (or
filters out all valid tags), it was previously hardcoded to return
`'latest'`. This caused the frontend to display `Latest version:
latest`.

I updated the GraphQL DTO to make `latestVersion` nullable, and modified
the service fallback and unit tests to return and expect `null` instead.

The frontend (`SettingsAdminVersionDisplay`) already has logic to handle
a falsy version and gracefully display `No latest version found`, so
this backend fix entirely resolves the UX issue without touching the
frontend.


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packages/twenty-server/src/engine/core-modules/admin-panel/__tests__/admin-panel.service.spec.ts

@@ -337,7 +337,7 @@ describe('AdminPanelVersionService', () => {
 
       expect(result).toEqual({
         currentVersion: '1.0.0',
-        latestVersion: 'latest',
+        latestVersion: null,
       });
     });
 
@@ -353,7 +353,7 @@ describe('AdminPanelVersionService', () => {
 
       expect(result).toEqual({
         currentVersion: '1.0.0',
-        latestVersion: 'latest',
+        latestVersion: null,
       });
     });
 

packages/twenty-server/src/engine/core-modules/admin-panel/dtos/version-info.dto.ts

@@ -5,6 +5,6 @@ export class VersionInfoDTO {
   @Field(() => String, { nullable: true })
   currentVersion?: string;
 
-  @Field(() => String)
-  latestVersion: string;
+  @Field(() => String, { nullable: true })
+  latestVersion?: string | null;
 }

packages/twenty-server/src/engine/core-modules/admin-panel/services/admin-panel-version.service.ts

@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { Injectable, Logger } from '@nestjs/common';
 
 import semver from 'semver';
 import * as z from 'zod';
@@ -9,6 +9,8 @@ import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twent
 
 @Injectable()
 export class AdminPanelVersionService {
+  private readonly logger = new Logger(AdminPanelVersionService.name);
+
   constructor(
     private readonly twentyConfigService: TwentyConfigService,
     private readonly secureHttpClientService: SecureHttpClientService,
@@ -36,15 +38,18 @@ export class AdminPanelVersionService {
         .filter((name) => name !== 'latest' && semver.valid(name));
 
       if (versions.length === 0) {
-        return { currentVersion, latestVersion: 'latest' };
+        return { currentVersion, latestVersion: null };
       }
 
       versions.sort((a, b) => semver.compare(b, a));
       const latestVersion = versions[0];
 
       return { currentVersion, latestVersion };
-    } catch {
-      return { currentVersion, latestVersion: 'latest' };
+    } catch (error) {
+      this.logger.warn(
+        `Failed to fetch latest version from DockerHub: ${error instanceof Error ? error.message : String(error)}`,
+      );
+      return { currentVersion, latestVersion: null };
     }
   }
 }