Feat: Build out server shell

Frontend/src/theme/runtime.ts

@@ -1,11 +1,12 @@
 // Path: Frontend/src/theme/runtime.ts
 
-import { defaultThemePresetPath } from "./presets";
+import { defaultThemePresetMeta, defaultThemePresetPath, resolveThemePresetPath } from "./presets";
 import { createCssVariableMap, isThemeModeName, validateThemeDefinition, type ThemeDefinition, type ThemeModeName } from "./schema";
 
 export type Theme = ThemeModeName;
 
 export const THEME_STORAGE_KEY = "theme";
+export const THEME_PRESET_STORAGE_KEY = "theme-preset";
 export const DEFAULT_THEME: Theme = "light";
 
 let activeThemeDefinition: ThemeDefinition | null = null;
@@ -21,6 +22,14 @@ const getRootElement = (): HTMLElement | null => {
 	return canUseDom() ? document.documentElement : null;
 };
 
+const persistThemePreset = (themeDefinition: ThemeDefinition): void => {
+	if (!canUseStorage()) {
+		return;
+	}
+
+	localStorage.setItem(THEME_PRESET_STORAGE_KEY, themeDefinition.id);
+};
+
 const setDocumentThemeMode = (theme: Theme): void => {
 	const rootElement = getRootElement();
 
@@ -71,10 +80,31 @@ export const getDocumentTheme = (): Theme => {
 
 export const applyThemeDefinition = (themeDefinition: ThemeDefinition, theme: Theme): void => {
 	activeThemeDefinition = themeDefinition;
+	persistThemePreset(themeDefinition);
 	setDocumentThemeMode(theme);
 	applyThemeVariables(themeDefinition, theme);
 };
 
+export const resolvePreferredThemePresetId = (): string => {
+	if (!canUseStorage()) {
+		return defaultThemePresetMeta.id;
+	}
+
+	const stored = localStorage.getItem(THEME_PRESET_STORAGE_KEY);
+
+	if (stored && resolveThemePresetPath(stored)) {
+		return stored;
+	}
+
+	return defaultThemePresetMeta.id;
+};
+
+export const resolvePreferredThemePresetPath = (): string => {
+	const presetId = resolvePreferredThemePresetId();
+
+	return resolveThemePresetPath(presetId) ?? defaultThemePresetPath;
+};
+
 export const initializeThemeRuntime = async (): Promise<ThemeDefinition | null> => {
 	if (typeof window === "undefined") {
 		return null;
@@ -88,7 +118,7 @@ export const initializeThemeRuntime = async (): Promise<ThemeDefinition | null>
 	if (!themeInitializationPromise) {
 		themeInitializationPromise = (async (): Promise<ThemeDefinition | null> => {
 			try {
-				const response = await fetch(defaultThemePresetPath, {
+				const response = await fetch(resolvePreferredThemePresetPath(), {
 					headers: {
 						Accept: "application/json",
 					},