chore: Update dependabot schedule from weekly to monthly

- Changed both gradle and github-actions ecosystems to monthly updates
- Updates will run on the 1st of each month at 09:00
- This reduces the frequency of dependency update PRs

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

Co-Authored-By: Claude <[email protected]>

Author: graycreate

.github/dependabot.yml

@@ -4,8 +4,8 @@ updates:
   - package-ecosystem: "gradle"
     directory: "/"
     schedule:
-      interval: "weekly"
-      day: "monday"
+      interval: "monthly"
+      day: 1
       time: "09:00"
     open-pull-requests-limit: 10
     groups:
@@ -47,7 +47,7 @@ updates:
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
-      interval: "weekly"
-      day: "monday"
+      interval: "monthly"
+      day: 1
       time: "09:00"
     open-pull-requests-limit: 5