fix(pi): exclude literal '.pi' from replacement in system prompt

Use negative lookbehind to avoid replacing '.pi' in paths like '.pi/agent'

modules/home/programs/terminal/pi/config/extensions/replace-pi-with-claude-code.ts

@@ -2,8 +2,9 @@ import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
 
 export default function replacePiWithClaudeCodeExtension(pi: ExtensionAPI) {
   pi.on("before_agent_start", async (event) => {
+    // Replace "pi" With "claude code" - Exclude Literal ".pi" (e.g. Paths)
     const transformedSystemPrompt = event.systemPrompt.replace(
-      /pi/gi,
+      /(?<!\.)pi/gi,
       "claude code",
     );