fix: dismiss stepper on script edit and improve function brace tracking

Stepper now auto-dismisses when the user edits the script body during
detection, preventing stale matchedLine replacements. Function-level
param() block detection uses brace depth counting instead of simple
equality check, correctly handling nested braces in function bodies.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/script-editor/ScriptTemplateEditor.tsx

@@ -67,6 +67,16 @@ export function ScriptTemplateEditor({ templateId, onBack, onSaved }: Props) {
 
   const { canShareScriptTemplate } = usePermissions()
 
+  // Dismiss stepper if user edits the script body during detection
+  const scriptBodyRef = form.script_body
+  useEffect(() => {
+    if (showStepper) {
+      setShowStepper(false)
+      setDetectedCandidates([])
+    }
+  // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [scriptBodyRef])
+
   // Load categories + template detail (if editing)
   useEffect(() => {
     const load = async () => {

frontend/src/lib/scriptParameterDetector.ts

@@ -127,19 +127,33 @@ function parseDefault(value: string | null, type: ScriptParameter['type']): stri
  */
 function findScriptLevelParamBlock(script: string): { start: number; end: number } | null {
   const lines = script.split('\n')
-  let inFunction = false
+  let functionBraceDepth = 0
   let paramStart = -1
   let parenDepth = 0
 
   for (let i = 0; i < lines.length; i++) {
     const trimmed = lines[i].trim()
 
+    // Track function blocks with brace depth to handle nested braces
     if (/^function\s+/i.test(trimmed)) {
-      inFunction = true
+      // Count braces on this line and subsequent lines
+      for (const ch of lines[i]) {
+        if (ch === '{') functionBraceDepth++
+        if (ch === '}') functionBraceDepth--
+      }
       continue
     }
 
-    if (!inFunction && /^param\s*\(/i.test(trimmed) && paramStart === -1) {
+    // Track braces while inside a function
+    if (functionBraceDepth > 0) {
+      for (const ch of lines[i]) {
+        if (ch === '{') functionBraceDepth++
+        if (ch === '}') functionBraceDepth--
+      }
+      continue
+    }
+
+    if (functionBraceDepth === 0 && /^param\s*\(/i.test(trimmed) && paramStart === -1) {
       paramStart = i
       for (let j = i; j < lines.length; j++) {
         for (const ch of lines[j]) {
@@ -151,10 +165,6 @@ function findScriptLevelParamBlock(script: string): { start: number; end: number
         }
       }
     }
-
-    if (inFunction && trimmed === '}') {
-      inFunction = false
-    }
   }
 
   return null