feat: css editor (#1542)

* feat: allow editing CSS from settings

---------

Co-authored-by: Carlos Valente <carlosvalente@pm.me>

refactor: style tweaks

apps/server/src/api-data/assets/assets.controller.ts

@@ -0,0 +1,41 @@
+import { defaultCss } from '../../user/styles/bundledCss.js';
+import type { Request, Response } from 'express';
+import { readCssFile, writeCssFile } from './assets.service.js';
+
+/**
+ * Exposes the contents of the cssOverride.css file
+ */
+export async function getCssOverride(_req: Request, res: Response) {
+  try {
+    const data = await readCssFile();
+    res.status(200).send(data);
+  } catch (error) {
+    res.status(500).send({ message: error });
+  }
+}
+
+/**
+ * Allows modifying the cssOverride.css file
+ */
+export async function postCssOverride(req: Request, res: Response) {
+  const { css } = req.body;
+
+  try {
+    await writeCssFile(css);
+    res.status(204).send();
+  } catch (error) {
+    res.status(500).send({ message: error });
+  }
+}
+
+/**
+ * Restores the default cssOverride.css file
+ */
+export async function restoreCss(_req: Request, res: Response) {
+  try {
+    await writeCssFile(defaultCss);
+    res.status(200).send(defaultCss);
+  } catch (error) {
+    res.status(500).send({ message: error });
+  }
+}