github: add needs-more-info automation workflow

Add GitHub Actions automation that helps manage issues requiring
additional information from reporters:

- Post an instruction comment when 'needs-more-info' label is added,
  requesting environment details, debug logs from multiple nodes,
  configuration files, and proper formatting
- Automatically remove the label when anyone comments
- Close the issue after 3 days if no response is provided
- Exempt needs-more-info labeled issues from the stale bot

The instruction comment includes guidance on:
- Required environment and debug information
- Collecting logs from both connecting and connected-to nodes
- Proper redaction rules (replace consistently, never remove IPs)
- Formatting requirements for attachments and Markdown
- Encouragement to discuss on Discord before filing issues

.github/workflows/needs-more-info-comment.yml

@@ -0,0 +1,28 @@
+name: Needs More Info - Post Comment
+
+on:
+  issues:
+    types: [labeled]
+
+jobs:
+  post-comment:
+    if: >-
+      github.event.label.name == 'needs-more-info' &&
+      github.repository == 'juanfont/headscale'
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          sparse-checkout: .github/label-response/needs-more-info.md
+          sparse-checkout-cone-mode: false
+
+      - name: Post instruction comment
+        run: gh issue comment "$NUMBER" --body-file .github/label-response/needs-more-info.md
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+          NUMBER: ${{ github.event.issue.number }}