refactor: Migrate from tera to minijinja (#1798)

## Which issue does this PR close?


- Closes #1772

## What changes are included in this PR?

Migrate from tera to minijinja for smaller deps and well-maintain crate.

## Are these changes tested?




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**This PR was primarily authored with Codex using GPT-5-Codex and then
hand-reviewed by me. I AM responsible for every change made in this PR.
I aimed to keep it aligned with our goals, though I may have missed
minor issues. Please flag anything that feels off, I'll fix it
quickly.**

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Signed-off-by: Xuanwo <[email protected]>
Co-authored-by: Renjie Liu <[email protected]>

Author: Xuanwo