fix: Minimize old Claude review comments errors (#786)

((COUNT++)) returns exit code 1 when COUNT is 0 because post-increment
evaluates to the previous value (0 = falsy). With set -e, this kills the
step after successfully minimizing the first comment. Use COUNT=$((COUNT
+ 1)) which always returns exit code 0.

---------

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

Author: maskarb

.github/workflows/amber-auto-review.yml

@@ -76,10 +76,10 @@ jobs:
             if [ -n "$id" ]; then
               if gh api graphql -f query='mutation($id: ID!) { minimizeComment(input: {subjectId: $id, classifier: OUTDATED}) { minimizedComment { isMinimized } } }' -f id="$id" 2>&1; then
                 echo "✓ Minimized $id"
-                ((COUNT++))
+                COUNT=$((COUNT + 1))
               else
                 echo "✗ Failed to minimize $id" >&2
-                ((ERRORS++))
+                ERRORS=$((ERRORS + 1))
               fi
             fi
           done <<< "$COMMENT_IDS"