CI: Add Dependabot configuration for weekly monorepo dependency updates (#2321)

[Talha12Shiekh]

Proposed Changes

Added .github/dependabot.yml to automate dependency management across the monorepo:

• Configured weekly automated dependency update checks for all package directories:
  • Root (/)
  • Web (/packages/web)
  • Vue (/packages/vue)
  • Native (/packages/native)
  • Core (/packages/reactivecore)
  • GitHub Actions (github-actions)

Linked Issues

• Fixes chore: add Dependabot config for automated dependency updates #2321 (ci: no automated dependency management — critically outdated dependencies)

Checklist

• Describe the proposed changes and how it'll improve the library experience.
• Please make sure that there are no linting errors in the code.
• Add a demo video/gif/screenshot to explain how did you test the fix.
• If it is a global change, try to add any side effects that it could have.
• Create a PR to add/update the docs (if needed) at here.
• Create a PR to add/update the storybook (if needed) at here.

Improvements to the Library Experience

• Automated Security & Maintenance: Automatically creates weekly PRs to keep dependencies and GitHub Actions up to date, eliminating manual tracking burden.

Side Effects

• None. Configuration file affects GitHub Dependabot scheduling only.