docs: add color palettes docs to React SDK (#529)

* Add color palettes documentation to React SDK reference

Generated-By: mintlify-agent

* Revise color palette setup instructions

Updated instructions for copying palette UUID and removed section on retrieving available palettes.

---------

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>
Co-authored-by: Giorgi Bagdavadze <12987425+notgiorgi@users.noreply.github.com>

Author: mintlify[bot]

references/react-sdk.mdx

@@ -106,6 +106,7 @@ type DashboardProps = {
     fontFamily?: string;            // Font family for all text
   };
   filters?: SdkFilter[];            // Apply filters programmatically
+  paletteUuid?: string;             // Color palette UUID for custom theming
   contentOverrides?: LanguageMap;   // Localization/translation overrides
   onExplore?: (options: {
     chart: SavedChart
@@ -464,6 +465,31 @@ Sets the background for the embedded content. Can be any color value or `'transp
 />
 ```
 
+## Color palettes
+
+You can customize the appearance of embedded dashboards using color palettes. Define multiple color palettes in your organization settings, then apply them to embedded dashboards using the `paletteUuid` prop.
+
+For more on customizing appearance, see [customizing the appearance of your project](/references/workspace/customizing-the-appearance-of-your-project).
+
+### Setting up color palettes
+
+1. Go to **Organization settings > Appearance** in Lightdash
+2. Define one or more color palettes
+3. Copy the palette UUID for the palette you want to use (or fetch from API `GET /api/v1/org/color-palettes`)
+
+### Applying a palette
+
+Pass the `paletteUuid` prop to the `Lightdash.Dashboard` component:
+
+```tsx
+<Lightdash.Dashboard
+  instanceUrl="https://app.lightdash.cloud"
+  token={token}
+  paletteUuid="your-palette-uuid"
+/>
+```
+
+
 ## Filtering data
 
 Filters can be passed to `<Lightdash.Dashboard/>` to filter dimensions by values. Filters are applied as AND operations, each further restricting results.