chore: replace GH_ACCESS_TOKEN with GitHub App token (#25518)

* chore: replace GH_ACCESS_TOKEN with GitHub App token

Replace personal access token (GH_ACCESS_TOKEN) with GitHub App token
generation using actions/create-github-app-token@v1 for improved security.

Updated workflows:
- draft-release.yml
- post-release.yml
- cleanup.yml
- cleanup-report.yml
- publish-report.yml
- i18n.yml

Benefits:
- Short-lived tokens (1 hour) vs long-lived PATs
- Fine-grained, scoped permissions
- Not tied to individual user accounts
- Better audit trail

Required setup:
- Create a GitHub App with contents:write permission
- Install the app on calcom/cal.com and calcom/test-results-2
- Add RELEASE_APP_ID and RELEASE_APP_PRIVATE_KEY secrets

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: rename secrets to CI_CAL_APP_ID and CI_CAL_APP_PRIVATE_KEY

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: use reusable workflow from calcom-ci-secrets for token generation

This isolates the GitHub App private key in a separate repository,
ensuring that compromised actions in cal.com can only access short-lived
tokens, not the key itself.

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: use explicit secret passing instead of secrets: inherit

Only pass the two required secrets (CI_CAL_APP_ID, CI_CAL_APP_PRIVATE_KEY)
to the reusable workflow instead of inheriting all secrets.

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: remove secrets block - using environment secrets from calcom-ci-secrets

Secrets are now loaded from the ci-github-app environment in
calcom-ci-secrets, so cal.com workflows no longer need to pass them.

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: revert to explicit secret passing

Environment secrets in cross-repo reusable workflows don't work as expected.
Secrets must be passed explicitly from the caller repository.

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

* chore: generate GitHub App token directly in workflows

Remove dependency on calcom-ci-secrets reusable workflow.
Token generation is now inline using actions/create-github-app-token
pinned to SHA 7e473efe3cb98aa54f8d4bac15400b15fad77d94 (v2.2.0).

Co-Authored-By: alex@cal.com <me@alexvanandel.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Anik Dhabal Babu <81948346+anikdhabal@users.noreply.github.com>

.github/workflows/draft-release.yml

@@ -17,13 +17,20 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      
+      - name: Generate GitHub App token
+        id: generate-token
+        uses: actions/create-github-app-token@7e473efe3cb98aa54f8d4bac15400b15fad77d94
+        with:
+          app-id: ${{ secrets.CI_CAL_APP_ID }}
+          private-key: ${{ secrets.CI_CAL_APP_PRIVATE_KEY }}
+          repositories: 'cal.com'
+
       - name: Checkout code
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
           ref: 'main'
-          token: ${{ secrets.GH_ACCESS_TOKEN }}
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Configure git
         run: |