Fix: images not rendering on GitHub side of GitHub integration (#10520)

* Fix: GitHub integration images missing due to unauthenticated image URLs (#10516)

Wire appendGuestLinkToImage as the default preprocessor in getMarkdown() so
all Huly→GitHub sync paths stamp a guest JWT token onto image URLs, allowing
GitHub's Camo proxy to fetch them without authentication.

Fixes #10516

Signed-off-by: Yulian Diaz <5605867+spatialy@users.noreply.github.com>

* Fix: expand inline arrow function to multi-line format per maintainer feedback

Signed-off-by: Yulian Diaz <5605867+spatialy@users.noreply.github.com>

---------

Signed-off-by: Yulian Diaz <5605867+spatialy@users.noreply.github.com>

services/github/pod-github/src/worker.ts

@@ -85,6 +85,7 @@ import { RepositorySyncMapper } from './sync/repository'
 import { ReviewCommentSyncManager } from './sync/reviewComments'
 import { ReviewThreadSyncManager } from './sync/reviewThreads'
 import { ReviewSyncManager } from './sync/reviews'
+import { appendGuestLinkToImage } from './sync/guest'
 import { UsersSyncManager, fetchViewerDetails } from './sync/users'
 import { errorToObj } from './sync/utils'
 import {
@@ -243,7 +244,10 @@ export class GithubWorker implements IntegrationManager {
       concatLink(this.getBranding()?.front ?? config.FrontURL, `/browse/?workspace=${this.workspace.uuid}`),
       // TODO storage URL
       concatLink(this.getBranding()?.front ?? config.FrontURL, `/files/${this.workspace.uuid}/`),
-      preprocessor
+      preprocessor ??
+        (async (nodes) => {
+          appendGuestLinkToImage(nodes, this.workspace.uuid)
+        })
     )
   }