feat: add /search command to highlight matches in conversation

Closes #32

src/lib/commands/slashCommands.ts

@@ -3,6 +3,7 @@ import { invoke } from "@tauri-apps/api/core";
 import { claudeStore } from "$lib/stores/claude";
 import { characterState } from "$lib/stores/character";
 import { setSkipNextGreeting } from "$lib/tauri";
+import { searchState } from "$lib/stores/search";
 
 export interface SlashCommand {
   name: string;
@@ -145,6 +146,20 @@ export const slashCommands: SlashCommand[] = [
       claudeStore.addLine("system", `Available commands:\n${helpText}`);
     },
   },
+  {
+    name: "search",
+    description: "Search within the conversation (use /search to clear)",
+    usage: "/search [query]",
+    execute: (args: string) => {
+      if (!args.trim()) {
+        searchState.clear();
+        claudeStore.addLine("system", "Search cleared");
+        return;
+      }
+      searchState.setQuery(args.trim());
+      claudeStore.addLine("system", `Searching for: "${args.trim()}"`);
+    },
+  },
   {
     name: "summarise",
     description: "Get a summary of the entire conversation",