Add Dependabot config for weekly npm and Actions updates (#28)

Groups minor/patch into a single PR and ignores major version
bumps; security updates still bypass the ignore rule.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: ejntaylor

.github/dependabot.yml

@@ -0,0 +1,28 @@
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+      - "frontend"
+    ignore:
+      - dependency-name: "*"
+        update-types: ["version-update:semver-major"]
+    groups:
+      non-major:
+        update-types: ["minor", "patch"]
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 3
+    labels:
+      - "dependencies"
+      - "ci"
+    ignore:
+      - dependency-name: "*"
+        update-types: ["version-update:semver-major"]