feat(design): add design scheme support and UI improvements

- Implement design scheme system with palette, typography, and feature customization
- Add color scheme dialog for user customization
- Update chat UI components to use design scheme values
- Improve header actions with consolidated deploy and export buttons
- Adjust layout spacing and styling across multiple components (chat, workbench etc...)
- Add model and provider info to chat messages
- Refactor workbench and sidebar components for better responsiveness

app/lib/.server/llm/stream-text.ts

@@ -9,6 +9,7 @@ import { LLMManager } from '~/lib/modules/llm/manager';
 import { createScopedLogger } from '~/utils/logger';
 import { createFilesContext, extractPropertiesFromMessage } from './utils';
 import { discussPrompt } from '~/lib/common/prompts/discuss-prompt';
+import type { DesignScheme } from '~/types/design-scheme';
 
 export type Messages = Message[];
 
@@ -38,6 +39,7 @@ export async function streamText(props: {
   summary?: string;
   messageSliceId?: number;
   chatMode?: 'discuss' | 'build';
+  designScheme?: DesignScheme;
 }) {
   const {
     messages,
@@ -51,6 +53,7 @@ export async function streamText(props: {
     contextFiles,
     summary,
     chatMode,
+    designScheme,
   } = props;
   let currentModel = DEFAULT_MODEL;
   let currentProvider = DEFAULT_PROVIDER.name;
@@ -120,6 +123,7 @@ export async function streamText(props: {
       cwd: WORK_DIR,
       allowedHtmlElements: allowedHTMLElements,
       modificationTagName: MODIFICATIONS_TAG_NAME,
+      designScheme,
       supabase: {
         isConnected: options?.supabaseConnection?.isConnected || false,
         hasSelectedProject: options?.supabaseConnection?.hasSelectedProject || false,