ci: skip the upstream-only jobs in forks

Forks inherit three jobs that cannot succeed there. Pages progress fails
on `gh api repos/<fork>/pages` (HTTP 404) after every push to main that
touches core/libs/prx, Pages fails at the release download or the
deployment, and the Build linux job waits for the self-hosted
`anyps5` runner, which forks don't have, until GitHub drops it. These
jobs now run only when the repository is not a fork.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.github/workflows/build.yml

@@ -421,7 +421,7 @@ jobs:
 
   linux:
     needs: eligibility
-    if: ${{ (github.event_name == 'push' || (github.event_name == 'workflow_dispatch' && inputs.linux)) && needs.eligibility.outputs.full == 'true' }}
+    if: ${{ !github.event.repository.fork && (github.event_name == 'push' || (github.event_name == 'workflow_dispatch' && inputs.linux)) && needs.eligibility.outputs.full == 'true' }}
     runs-on: [self-hosted, linux, x64, anyps5]
     timeout-minutes: 60
     env:

.github/workflows/pages-progress.yml

@@ -18,6 +18,7 @@ concurrency:
 
 jobs:
   progress:
+    if: ${{ !github.event.repository.fork }}
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:

.github/workflows/pages.yml

@@ -33,7 +33,7 @@ concurrency:
 
 jobs:
   pages:
-    if: github.event_name != 'workflow_run' || github.event.workflow_run.conclusion == 'success'
+    if: ${{ !github.event.repository.fork && (github.event_name != 'workflow_run' || github.event.workflow_run.conclusion == 'success') }}
     runs-on: ubuntu-latest
     environment:
       name: github-pages