Clarify upstream merge and Renovate actions on PRs

[withinfocus]

🎟️ Tracking

Internal discussions after seeing some Renovate activity.

📔 Objective

Adds guidance around not continually merging the upstream into Renovate branches given the effects and limitations, as well as in general.

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[github-actions]

Checkmarx One – Scan Summary & Details – 779e0ec9-07b2-42e6-8386-f1e7388999c2

Great job! No new security vulnerabilities introduced in this pull request

[eliykat]

I wasn't in the internal discussions, but some input from the tech lead perspective.

[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

This PR adds a new "Keeping your branch up to date" section to branching.md and rewrites the "Changing a generated PR" section in dependencies/index.md to clarify Renovate branch interaction. The two files are cross-linked, and the new dependencies content correctly defers to the new branching section for general guidance while documenting Renovate-specific behavior. The author has already incorporated reviewer feedback to present rebase and merge neutrally with the force-push tradeoff called out, and to clarify that CI on main (post-merge) is the safety net rather than pre-merge sync. Two earlier grammar suggestions have been resolved in the current diff.

Code Review Details

No new findings. Cross-link slug #keeping-your-branch-up-to-date resolves to the new heading, terminology is consistent with the rest of the file, and prior inline suggestions are reflected in the current text.

[eliykat]

All my concerns have been addressed, thank you!