security(ci): add Dependabot config for npm and GitHub Actions

Closes SEC-008: Configure Dependabot for npm and GitHub Actions
Coverage: 87.36% (unchanged)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ihor-sokoliuk

.github/dependabot.yml

@@ -0,0 +1,22 @@
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+    open-pull-requests-limit: 5
+    groups:
+      dev-dependencies:
+        patterns: ["*"]
+        dependency-type: development
+    ignore:
+      - dependency-name: "*"
+        update-types: ["version-update:semver-major"]  # major bumps need manual review
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+    open-pull-requests-limit: 5