ci: use PR-based sync for Discord channels

- Replace direct commit-and-push with peter-evans/create-pull-request to open an automated PR (branch: automation/discord-channel-sync) updating discord_data/channels.json.
- Add pull-requests: write permission and a concurrency group (discord-channel-sync) so runs are coordinated and not canceled.
- The workflow now creates a descriptive PR against the repository default branch instead of pushing changes directly.

Author: tazlin

.github/workflows/discord-channel-sync.yml

@@ -8,6 +8,11 @@ on:
 
 permissions:
   contents: write
+  pull-requests: write
+
+concurrency:
+  group: discord-channel-sync
+  cancel-in-progress: false
 
 jobs:
   sync-channels:
@@ -33,11 +38,18 @@ jobs:
         run: |
           git diff --quiet discord_data/channels.json && echo "changed=false" >> $GITHUB_OUTPUT || echo "changed=true" >> $GITHUB_OUTPUT
 
-      - name: Commit updated channel inventory
+      - name: Create PR with updated channel inventory
         if: steps.diff.outputs.changed == 'true'
-        run: |
-          git config user.name "github-actions[bot]"
-          git config user.email "github-actions[bot]@users.noreply.github.com"
-          git add discord_data/channels.json
-          git commit -m "chore: sync Discord channel inventory"
-          git push
+        uses: peter-evans/create-pull-request@v7
+        with:
+          commit-message: "chore: sync Discord channel inventory"
+          title: "chore: sync Discord channel inventory"
+          body: |
+            Automated update generated by the Discord Channel Sync workflow.
+
+            This PR updates the Discord channel inventory file:
+            - discord_data/channels.json
+          branch: automation/discord-channel-sync
+          base: ${{ github.event.repository.default_branch }}
+          add-paths: |
+            discord_data/channels.json