chore(ci): update workflows for new triage system (#1217)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/issue-label.yml

@@ -0,0 +1,18 @@
+name: Auto-label new issues
+
+on:
+  issues:
+    types: [opened]
+
+jobs:
+  add-triage:
+    if: github.event.issue.pull_request == null
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+    steps:
+      - run: gh issue edit "$NUMBER" --add-label triage
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+          NUMBER: ${{ github.event.issue.number }}