chore: Add Dependabot for npm and GitHub Actions (#152)

* Add Dependabot configuration for npm and GitHub Actions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* chore: use bun ecosystem and add Dependabot cooldowns

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Matthew Breedlove <sirmalloc@gmail.com>

.github/dependabot.yml

@@ -0,0 +1,30 @@
+version: 2
+updates:
+  - package-ecosystem: bun
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+    open-pull-requests-limit: 10
+    cooldown:
+      semver-major-days: 30
+      semver-minor-days: 7
+      semver-patch-days: 3
+    groups:
+      dev-dependencies:
+        dependency-type: development
+        update-types:
+          - minor
+          - patch
+      production-dependencies:
+        dependency-type: production
+        update-types:
+          - minor
+          - patch
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+    open-pull-requests-limit: 5