Replace Streamdown with a plugin-free markdown renderer

The assistant only ever renders prose, links and the odd list, but
Streamdown's plugin set dragged in shiki, mermaid and katex — and
streamdown core declares mermaid as a hard dependency, so dropping the
plugins alone would have left it installed. Rendering now runs on the
same unified pipeline Streamdown used internally, minus the plugin
surface: remark-parse -> remark-gfm -> remark-rehype -> rehype-sanitize
-> hast-util-to-jsx-runtime. GFM, streaming repair and the link-safety
hook all survive; fenced code renders as plain <pre>. Net -264/+101
packages.

remend now runs only while a part is still streaming. On settled text it
reads `*$89*` as an unclosed italic — the `$` throws off its
closing-delimiter scan — and appends a stray `*` that parses as an empty
bullet. Italic prices are ordinary storefront copy, so that would have
shown up in production.

Route-relative links go through next/link in the same tab; sending a
shopper to a product page in a new tab would strand the conversation
behind it. Only external destinations get the confirmation dialog.

code-block.tsx and tool.tsx were the sole users of shiki and had no
importers, so both are gone.

Also folded in two unrelated changes that were already in the tree: the
loader move out of app/components/ui, and dropping the fade on the
command palette so it opens instantly.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KuySwKLSF4uEPpZjHkdHBP

components/shopify/account-form.tsx

@@ -4,7 +4,7 @@ import React, { useState } from 'react';
 import Link from 'next/link';
 import { useRouter } from 'next/navigation';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 
 export interface AccountFormField {
   name: string;

components/shopify/cart-drawer.tsx

@@ -3,7 +3,7 @@
 import React, { useState } from 'react';
 import { useCartStore, redirectToCheckout } from '@/hooks/use-shopify-cart';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import {
   Sheet,
   SheetContent,

components/shopify/collection-detail.tsx

@@ -6,7 +6,7 @@ import ProductCard from './product-card';
 import ProductFilters, { type ProductFilterFacet } from './product-filters';
 import ProductToolbar from './product-toolbar';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import {
   getCollectionProductsPage,
   type CollectionSortKey,

components/shopify/product-detail/product-detail-info.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import { RiSubtractLine, RiAddLine } from '@remixicon/react';
 import ShopPayButton from '@/components/shopify/shop-pay-button';
 import type { ProductOption, ProductOptionValue } from '@/hooks/use-shopify-products';

components/shopify/products.tsx

@@ -4,7 +4,7 @@ import React, { useState, useEffect } from 'react';
 import ProductCard from './product-card';
 import { getProductsPage } from '@/hooks/use-shopify-products';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 
 interface ProductImage {
   url: string;

components/shopify/search-dialog.tsx

@@ -11,7 +11,7 @@ import {
   CommandItem,
 } from '@/components/ui/command';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import { RiSearchLine, RiImageLine, RiCloseLine } from '@remixicon/react';
 import {
   searchSuggestions,
@@ -111,7 +111,7 @@ const SearchDialog: React.FC = () => {
               if (event.key === 'Enter') goToSearchPage();
             }}
           />
-          <div className="absolute right-2 top-0 flex h-9 items-center gap-1">
+          <div className="absolute right-2 top-0 flex h-12 items-center gap-1">
             {hasQuery && (
               <Button
                 onClick={() => setTerm('')}

components/shopify/search-results.tsx

@@ -6,7 +6,7 @@ import ProductCard from './product-card';
 import ProductFilters from './product-filters';
 import ProductToolbar from './product-toolbar';
 import { Button } from '@/components/ui/button';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import {
   searchProducts,
   type SearchFilter,

components/shopify/shop-pay-button.tsx

@@ -3,7 +3,7 @@
 import React from 'react';
 import { SHOPIFY_STORE_DOMAIN } from '@/services/shopify/client';
 import ShopPayLogo from '@/components/shopify/shop-pay-logo';
-import { Loader } from '@/app/components/ui/loader';
+import { Loader } from '@/components/ui/loader';
 import { Button } from '@/components/ui/button';
 
 export interface ShopPayVariant {

components/shopify/store-assistant.tsx

@@ -393,6 +393,11 @@ const StoreAssistant: React.FC = () => {
                       return (
                         <MessageResponse
                           key={index}
+                          // Only repair half-written markdown while it streams;
+                          // settled text is rendered exactly as sent.
+                          isAnimating={
+                            status === 'streaming' && part.state === 'streaming'
+                          }
                           linkSafety={{
                             enabled: true,
                             onLinkCheck: isInternalLink,