actually need to test no diff detected case

Author: LFDanLu

.github/workflows/weekly-api-diff.yml

@@ -1,6 +1,8 @@
 name: Weekly API Diff
 
 on:
+  push:
+    branches: [tsdiff_script]  # temporary: remove before merging to main
   schedule:
     - cron: '0 17 * * 1'  # Monday 9am PST / 10am PDT (GH Actions cron is UTC)
   workflow_dispatch:        # manual trigger for testing
@@ -56,18 +58,20 @@ jobs:
             echo "(first run — no previous diff to compare against)" > /tmp/weekly-delta.txt
           fi
 
-          cd snapshots
-          git config user.email "github-actions@github.com"
-          git config user.name "GitHub Actions"
-          git add diffs/$TODAY.txt
-          git commit -m "weekly api diff $TODAY"
-          git push
+          if [ -s /tmp/diff-current.txt ]; then
+            cd snapshots
+            git config user.email "github-actions@github.com"
+            git config user.name "GitHub Actions"
+            git add diffs/$TODAY.txt
+            git commit -m "weekly api diff $TODAY"
+            git push
+          fi
 
       # Summarize with GitHub Models (free via GITHUB_TOKEN) and post to Slack
       - name: Summarize and post to Slack
         env:
           SLACK_TSDIFF_CHROMATIC_BOT_TOKEN: ${{ secrets.SLACK_TSDIFF_CHROMATIC_BOT_TOKEN }}
-          SLACK_CHANNEL_ID: ${{ secrets.SLACK_CHANNEL_ID }}
+          SLACK_CHANNEL_ID: ${{ secrets.TEST_SLACK_ID }}
           GITHUB_TOKEN: ${{ github.token }}
         run: |
           python3 << 'PYEOF'