chore(i18n): stop tracking generated locale/*.po copies

az.po/ru.po are regenerated (overwritten) by the az_locale app on every
`bench migrate` via setup_locale, so tracking them dirtied the working tree and
blocked `git pull` ("local changes would be overwritten by merge"). Untrack them
and gitignore locale/*.po; main.pot (extraction template) stays tracked, and the
masters remain the source of truth in the az_locale repo.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -9,3 +9,8 @@ __pycache__
 # Local e-taxes cabinet probes — live JWTs, Redux dumps, screenshots with real
 # taxpayer data. Whole folder ignored.
 .etaxes_notes/
+# Per-app translation copies (az.po/ru.po) are generated and overwritten by the
+# az_locale app on every `bench migrate` (setup_locale). Masters live in the
+# az_locale repo, so keeping these tracked only dirties the tree and blocks
+# `git pull`. Untrack them; main.pot (the extraction template) stays tracked.
+taxes_az/locale/*.po