## Summary
Fixes the GUI language dropdown to show territory variants when
translation files include country codes.
**Before:** "Portuguese" for both `pt_BR` and `pt_PT`
**After:** "Portuguese (Brazil)" and "Portuguese (Portugal)"
Also fixes the same ambiguity for Chinese and any other language with
country variants.
## Implementation
Uses `QLocale::territoryToString()` alongside the existing
`QLocale::languageToString()` to construct display labels. When no
territory exists (e.g., `en`, `ja`), the label is unchanged.
## Edge cases
- No-territory locales (`en`, `ja`): unchanged —
`QLocale::territoryToString(AnyTerritory)` returns empty, guard
preserves plain language name
- Territory names are locale-translated (not hardcoded English) — they
follow the current UI language, same as `languageToString()`
- `zh_CN` → "Chinese (China)" / `zh_TW` → "Chinese (Taiwan)"
(territory-based, unlike the PS3 system language dropdown which uses
Simplified/Traditional script names — this is appropriate for the GUI
translator selector context)
## Test Plan
- [ ] Language menu shows "Portuguese (Brazil)" when `rpcs3_pt_BR.qm` is
present
- [ ] Language menu shows "Chinese (China)" when `rpcs3_zh_CN.qm` is
present
- [ ] Plain languages (`en`, `ja`) continue to show without parens
---
<details>
<summary>Review note: territory strings in UI locale</summary>
Territory names render in the current UI language (not forced English).
This matches `QLocale::languageToString()` behavior and is consistent
with how the rest of the menu renders. If hardcoded English labels are
preferred, that can be added after review.
</details>
Fixes#18215
