Skip call sign auto-detection inside code and pre elements (#28)

* Initial plan

* Skip call sign auto-detection inside code and pre elements

Agent-Logs-Url: https://github.com/phieri/callsign.js/sessions/065dc63f-540e-41b2-bf49-ee07d2ecfa63

Co-authored-by: phieri <12006381+phieri@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: phieri <12006381+phieri@users.noreply.github.com>

Author: Copilot

src/callsign.js

@@ -389,11 +389,13 @@ class Callsign extends HTMLElement {
       NodeFilter.SHOW_TEXT,
       {
         acceptNode(node) {
-          // Skip script and style elements
+          // Skip script, style, code and pre elements
           const parent = node.parentElement;
           if (!parent || parent.tagName === 'SCRIPT' || 
               parent.tagName === 'STYLE' || 
-              parent.tagName === 'CALL-SIGN') {
+              parent.tagName === 'CALL-SIGN' ||
+              parent.tagName === 'CODE' ||
+              parent.tagName === 'PRE') {
             return NodeFilter.FILTER_REJECT;
           }
           // Only accept nodes with potential call signs