chore: add engineering standards (dependabot)

[nikzen]

Automated rollout from engineering-standards.

Base (always included):

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

Detected scope: docker

[github-actions]

* 6873a04fabed084a5b777d59ecd397e4b764a9ac chore: add engineering standards (dependabot, docker)
|   - Error: Could not find a certificate with BDE15DDCE302F9E417F426D9A575DDEB3DB7D052 in the policy file
* 89731fadda94d348c25348354a462a13576a0da3 fix: add libgcc to final image so that minijinja-cli actually works
    - Trust root.

Failed to authenticate commits.

Error: Could not verify commits 89731fadda94d348c25348354a462a13576a0da3..6873a04fabed084a5b777d59ecd397e4b764a9ac

Caused by:
    0: While verifying commit 6873a04fabed084a5b777d59ecd397e4b764a9ac
    1: Could not find a certificate with BDE15DDCE302F9E417F426D9A575DDEB3DB7D052 in the policy file