Add smart updateContentCommand execution

[nomicode]

Currently, the only command we run is trunk upgrade, but we plan to expand this in the future (probably with a dedicated shell script to collect the additional commands).

However, we want to avoid running trunk upgrade unless a repository is actually using Trunk. The same will be true for Sourcery.

For the GitHub CLI, logging in should be opt-in per repository.

For Trunk and Sourcery, we should test for the presence of associated configuration files. And for GitHub, we could test for a presence of Codespace secret.

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Tasks:

• Only initialize Trunk if a Trunk config exists
• Only initialize Sourcery if a Sourcery config exists
• Only log in to GitHub if a specific Codespace secret is set in the environment

[nomicode]

Trunk behavior is addressed by:

• feat: Run trunk upgrade when a Trunk is detected #30