fix: escape regex metacharacters in stateExtractField (#741)

stateReplaceField properly escaped fieldName before building the regex,
but stateExtractField did not. Field names containing regex metacharacters
could cause incorrect matches or regex errors.

Co-authored-by: Ethan Hurst <ethan.hurst@outlook.com.au>

get-shit-done/bin/lib/state.cjs

@@ -151,7 +151,8 @@ function cmdStateUpdate(cwd, field, value) {
 // ─── State Progression Engine ────────────────────────────────────────────────
 
 function stateExtractField(content, fieldName) {
-  const pattern = new RegExp(`\\*\\*${fieldName}:\\*\\*\\s*(.+)`, 'i');
+  const escaped = fieldName.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+  const pattern = new RegExp(`\\*\\*${escaped}:\\*\\*\\s*(.+)`, 'i');
   const match = content.match(pattern);
   return match ? match[1].trim() : null;
 }