feat(theme): add sunset theme (@catdogdonkey) (monkeytypegame#6467)

### Description

Just added a new theme (I tried my best to not make this similar to any
themes, but if it is similar to one, please tell me!)

#### Screenshots

![sunset
home](https://github.com/user-attachments/assets/dc02a1b8-047e-4097-a9a4-d42998116fdb)

![sunset
test](https://github.com/user-attachments/assets/ffc61f2b-43bd-4ef3-953a-0495a22721b7)

![sunset
settings](https://github.com/user-attachments/assets/bf74a5ee-346e-4f14-9ec9-d3ea4d293c03)

![sunset
values](https://github.com/user-attachments/assets/cf87d0d7-b954-4862-b5ec-8d14ffea5d5f)


### Checks

- [ ] Adding quotes?
- [ ] Make sure to include translations for the quotes in the
description (or another comment) so we can verify their content.
- [x] Adding a language or a theme?
- [ ] If is a language, did you edit `_list.json`, `_groups.json` and
add `languages.json`?
  - [x] If is a theme, did you add the theme.css?
- Also please add a screenshot of the theme, it would be extra awesome
if you do so!
- [x] Check if any open issues are related to this PR; if so, be sure to
tag them below.
- [x] Make sure the PR title follows the Conventional Commits standard.
(https://www.conventionalcommits.org for more info)
- [x] Make sure to include your GitHub username prefixed with @ inside
parentheses at the end of the PR title.



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Author: catdogdonkey

frontend/static/themes/_list.json

@@ -1279,5 +1279,12 @@
     "mainColor": "#41ce5c",
     "subColor": "#788386",
     "textColor": "#ccdae6"
+  },
+  {
+    "name": "sunset",
+    "bgColor": "#211e24",
+    "mainColor": "#f79777",
+    "subColor": "#5b578e",
+    "textColor": "#f4e0c9"
   }
 ]

frontend/static/themes/sunset.css

@@ -0,0 +1,26 @@
+:root {
+  --bg-color: #211e24;
+  --main-color: #f79777;
+  --caret-color: #ffca99;
+  --sub-color: #5b578e;
+  --sub-alt-color: #161319;
+  --text-color: #f4e0c9;
+  --error-color: #66a1ff;
+  --error-extra-color: #376ca4;
+  --colorful-error-color: #66a1ff;
+  --colorful-error-extra-color: #376ca4;
+}
+
+nav > .textButton:nth-child(1),
+nav > .textButton:nth-child(2),
+nav > .textButton:nth-child(3),
+nav > .textButton:nth-child(4) {
+  color: #f79777;
+}
+
+nav > .textButton:nth-child(1):hover,
+nav > .textButton:nth-child(2):hover,
+nav > .textButton:nth-child(3):hover,
+nav > .textButton:nth-child(4):hover {
+  color: #ffca99;
+}