Add GitHub Action to suggest maintenance branches for PRs targeting master (#2444)

Author: sensei-hacker

.github/workflows/pr-branch-suggestion.yml

@@ -0,0 +1,37 @@
+name: PR Branch Suggestion
+
+on:
+  pull_request_target:
+    types: [opened]
+    branches:
+      - master
+
+jobs:
+  suggest-branch:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Suggest maintenance branch
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const comment = `### Branch Targeting Suggestion
+
+            You've targeted the \`master\` branch with this PR. Please consider if a version branch might be more appropriate:
+
+            - **\`maintenance-9.x\`** - If your change is backward-compatible and won't create compatibility issues between INAV firmware and Configurator 9.x versions. This will allow your PR to be included in the next 9.x release.
+
+            - **\`maintenance-10.x\`** - If your change introduces compatibility requirements between firmware and configurator that would break 9.x compatibility. This is for PRs which will be included in INAV 10.x
+
+            If \`master\` is the correct target for this change, no action is needed.
+
+            ---
+            *This is an automated suggestion to help route contributions to the appropriate branch.*`;
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: comment
+            });