ci: Add /area and /milestone commands to PR label sync

Extends the existing /kind label sync workflow to also handle /area
and /milestone directives in the PR body. This commit uses the same
gh CLI pattern as other steps in the workflow. This provides a a native
GitHub replacement for the /area and /milestone commands that prow
currently provides.

Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>

Author: hickeyma

.github/workflows/pr-kind-label.yaml

@@ -1,4 +1,4 @@
-name: Apply kind labels from PR body
+name: Apply kind/area labels and milestone from PR body
 
 on:
   pull_request_target:
@@ -34,3 +34,40 @@ jobs:
               gh pr edit "$PR_NUMBER" --repo "$REPO" --add-label "kind/$kind" || \
                 echo "::warning::Label 'kind/$kind' not found in repository"
             done
+
+      - name: Sync area labels
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR_BODY: ${{ github.event.pull_request.body }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          REPO: ${{ github.repository }}
+        run: |
+          # Remove existing area/* labels
+          gh pr view "$PR_NUMBER" --repo "$REPO" --json labels \
+            -q '.labels[].name | select(startswith("area/"))' | \
+            while IFS= read -r label; do
+              gh pr edit "$PR_NUMBER" --repo "$REPO" --remove-label "$label"
+            done
+
+          # Extract /area values from PR body and apply labels
+          printf '%s' "$PR_BODY" | tr -d '\r' | grep '^/area ' | \
+            sed 's|^/area ||' | sort -u | \
+            while IFS= read -r area; do
+              [ -z "$area" ] && continue
+              gh pr edit "$PR_NUMBER" --repo "$REPO" --add-label "area/$area" || \
+                echo "::warning::Label 'area/$area' not found in repository"
+            done
+
+      - name: Set milestone
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR_BODY: ${{ github.event.pull_request.body }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          REPO: ${{ github.repository }}
+        run: |
+          # Use the last /milestone directive in the PR body
+          milestone=$(printf '%s' "$PR_BODY" | tr -d '\r' | grep '^/milestone ' | \
+            sed 's|^/milestone ||' | tail -n 1)
+          [ -z "$milestone" ] && exit 0
+          gh pr edit "$PR_NUMBER" --repo "$REPO" --milestone "$milestone" || \
+            echo "::warning::Milestone '$milestone' not found in repository"