Enable grouped updates for Dependabot

Configure Dependabot to batch updates by package ecosystem:
- GitHub Actions updates grouped together
- npm dependencies grouped together

This reduces PR noise by combining multiple dependency updates into single PRs per ecosystem.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/dependabot.yml

@@ -8,6 +8,10 @@ updates:
     commit-message:
       prefix: "chore"
       include: "scope"
+    groups:
+      github-actions:
+        patterns:
+          - "*"
 
   # Enable version updates for npm
   - package-ecosystem: "npm"
@@ -16,4 +20,8 @@ updates:
       interval: "weekly"
     commit-message:
       prefix: "chore"
-      include: "scope"
+      include: "scope"
+    groups:
+      npm-dependencies:
+        patterns:
+          - "*"