perf: Implement terminal reuse for tags sharing the same content regex (e.g., `/(?s:.*)/`)

[Ki-Seki]

In build_cfg(): There may be many tags with "/(?s:.*)/" pattern, which can be inefficient. Implement terminal reuse for tags sharing the same content regex (e.g., /(?s:.*)/)

TODO Line:

GIMKit/src/gimkit/dsls.py

Line 98 in 3fa5e49

# TODO: There may be many tags with "/(?s:.*)/" pattern, which can be inefficient.

This is an optimized version of PR #167