fix: resolve XSS vulnerability in Terminal component search highlighting

- Created new HighlightedText component for safe text highlighting
- Replaced unsafe {@html} usage with component-based approach
- Maintains full search functionality without security risks

src/lib/components/HighlightedText.svelte

@@ -0,0 +1,61 @@
+<script lang="ts">
+  export let content: string;
+  export let searchQuery: string;
+
+  interface TextPart {
+    text: string;
+    isMatch: boolean;
+  }
+
+  function getHighlightedParts(text: string, query: string): TextPart[] {
+    if (!query) {
+      return [{ text, isMatch: false }];
+    }
+
+    const escapedQuery = query.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+    const regex = new RegExp(`(${escapedQuery})`, "gi");
+    const parts: TextPart[] = [];
+    let lastIndex = 0;
+    let match: RegExpExecArray | null;
+
+    while ((match = regex.exec(text)) !== null) {
+      // Add non-matching text before the match
+      if (match.index > lastIndex) {
+        parts.push({
+          text: text.slice(lastIndex, match.index),
+          isMatch: false,
+        });
+      }
+
+      // Add the matching text
+      parts.push({
+        text: match[1],
+        isMatch: true,
+      });
+
+      lastIndex = regex.lastIndex;
+    }
+
+    // Add any remaining text after the last match
+    if (lastIndex < text.length) {
+      parts.push({
+        text: text.slice(lastIndex),
+        isMatch: false,
+      });
+    }
+
+    return parts;
+  }
+
+  $: parts = getHighlightedParts(content, searchQuery);
+</script>
+
+<span class="whitespace-pre-wrap">
+  {#each parts as part, index (index)}
+    {#if part.isMatch}
+      <mark class="search-highlight">{part.text}</mark>
+    {:else}
+      {part.text}
+    {/if}
+  {/each}
+</span>

src/lib/components/Terminal.svelte

@@ -3,6 +3,7 @@
   import { afterUpdate } from "svelte";
   import ConversationTabs from "./ConversationTabs.svelte";
   import Markdown from "./Markdown.svelte";
+  import HighlightedText from "./HighlightedText.svelte";
   import { searchState, searchQuery } from "$lib/stores/search";
 
   let terminalElement: HTMLDivElement;
@@ -71,13 +72,6 @@
     });
   }
 
-  function highlightText(text: string, query: string): string {
-    if (!query) return text;
-    const escapedQuery = query.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
-    const regex = new RegExp(`(${escapedQuery})`, "gi");
-    return text.replace(regex, '<mark class="search-highlight">$1</mark>');
-  }
-
   $: {
     if (currentSearchQuery && lines.length > 0) {
       const escapedQuery = currentSearchQuery.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
@@ -134,10 +128,7 @@
           {#if line.type === "assistant"}
             <Markdown content={line.content} searchQuery={currentSearchQuery} />
           {:else}
-            <!-- eslint-disable-next-line svelte/no-at-html-tags -- Search highlighting on internal terminal content -->
-            <span class="whitespace-pre-wrap"
-              >{@html highlightText(line.content, currentSearchQuery)}</span
-            >
+            <HighlightedText content={line.content} searchQuery={currentSearchQuery} />
           {/if}
         </div>
       {/each}