feat: add assistant board styling tools

apps/nextjs/src/components/assistant/assistant-board-settings.ts

@@ -0,0 +1,33 @@
+import type { AssistantBoardSettingsChanges } from "./assistant-tool-contracts";
+
+export const assistantBoardSettingKeys = [
+  "pageTitle",
+  "metaTitle",
+  "logoImageUrl",
+  "faviconImageUrl",
+  "backgroundImageUrl",
+  "backgroundImageAttachment",
+  "backgroundImageRepeat",
+  "backgroundImageSize",
+  "primaryColor",
+  "secondaryColor",
+  "opacity",
+  "customCss",
+  "iconColor",
+  "itemRadius",
+  "disableStatus",
+] as const satisfies readonly (keyof AssistantBoardSettingsChanges)[];
+
+const comparableValue = (value: unknown) => (value === null ? "" : value);
+
+export const getChangedBoardSettings = (current: AssistantBoardSettingsChanges, next: AssistantBoardSettingsChanges) =>
+  Object.fromEntries(
+    assistantBoardSettingKeys.flatMap((key) =>
+      comparableValue(current[key]) === comparableValue(next[key]) ? [] : [[key, next[key]]],
+    ),
+  ) as AssistantBoardSettingsChanges;
+
+export const getCustomCssWarnings = (css: string) => ({
+  importsStylesheet: /@import\b/iu.test(css),
+  loadsRemoteResource: /url\(\s*["']?https?:\/\//iu.test(css),
+});