chore: add engineering standards (dependabot)

[nikzen]

Automated rollout from engineering-standards.

Base (always included):

• .github/dependabot.yml – automated dependency updates (Dependabot)
• Ecosystems: github-actions
• Grouped PRs: major updates separate from minor+patch
• Cooldown: 14 days

Detected scope: generic

[CLAassistant]

All committers have signed the CLA.

[github-actions]

* 4ee1723a994ff398f3d05d81ac27292d521f72ea chore: add engineering standards (dependabot, generic)
|   - Error: Could not find a certificate with BDE15DDCE302F9E417F426D9A575DDEB3DB7D052 in the policy file
* a00534b2cf567dfaea6699be59bc8b92a65dee79 fix(fos-rotate-passwords): correct script name
    - Trust root.

Failed to authenticate commits.

Error: Could not verify commits a00534b2cf567dfaea6699be59bc8b92a65dee79..4ee1723a994ff398f3d05d81ac27292d521f72ea

Caused by:
    0: While verifying commit 4ee1723a994ff398f3d05d81ac27292d521f72ea
    1: Could not find a certificate with BDE15DDCE302F9E417F426D9A575DDEB3DB7D052 in the policy file