fix: handle multi-line param() attributes in parameter detection

Switch from single multiline regex to line-by-line scanning that skips
PowerShell attribute decorators like [Parameter(Mandatory=$true)] and
[ValidateSet(...)]. This correctly detects parameters with attribute
lines above them (the most common real-world pattern).

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

frontend/src/lib/scriptParameterDetector.ts

@@ -178,27 +178,36 @@ function extractParamBlockCandidates(
   block: { start: number; end: number }
 ): ParameterCandidate[] {
   const lines = script.split('\n')
-  const blockText = lines.slice(block.start, block.end + 1).join('\n')
   const candidates: ParameterCandidate[] = []
 
-  const paramRegex = /(?:\[(\w+)\])?\s*\$(\w+)(?:\s*=\s*(.+?))?(?:\s*,\s*$|\s*$|\s*\))/gm
-  let match: RegExpExecArray | null
+  // Scan each line in the param block for $VarName patterns.
+  // Lines with [Parameter(...)], [ValidateSet(...)], etc. don't contain $VarName
+  // so they are naturally skipped. The type annotation [string], [int], etc.
+  // appears on the same line as $VarName.
+  const varLineRegex = /(?:\[(\w+)\])?\s*\$(\w+)(?:\s*=\s*(.+?))?(?:\s*,?\s*$)/
+
+  for (let i = block.start; i <= block.end; i++) {
+    const trimmed = lines[i].trim()
+
+    // Skip attribute lines like [Parameter(...)], [ValidateSet(...)], etc.
+    if (/^\[(?:Parameter|ValidateSet|ValidateRange|ValidatePattern|ValidateScript|ValidateLength|ValidateCount|Alias|AllowNull|AllowEmptyString|AllowEmptyCollection)\s*\(/i.test(trimmed)) {
+      continue
+    }
+
+    const match = trimmed.match(varLineRegex)
+    if (!match) continue
 
-  while ((match = paramRegex.exec(blockText)) !== null) {
     const typeAnnotation = match[1] || null
     const varName = match[2]
     const rawDefault = match[3]?.trim() ?? null
 
+    // Skip if type looks like an attribute we didn't catch above
     if (typeAnnotation && /^Parameter$/i.test(typeAnnotation)) continue
 
     const key = toSnakeCase(varName)
     const { type, sensitive, reason } = inferType(typeAnnotation, rawDefault, varName)
     const defaultValue = parseDefault(rawDefault, type)
 
-    const lineIndex = lines.findIndex((line, idx) =>
-      idx >= block.start && idx <= block.end && line.includes(`$${varName}`)
-    )
-
     candidates.push({
       variableName: `$${varName}`,
       suggestedKey: key,
@@ -207,8 +216,8 @@ function extractParamBlockCandidates(
       sensitive,
       defaultValue,
       source: 'param_block',
-      lineNumber: lineIndex !== -1 ? lineIndex + 1 : block.start + 1,
-      matchedLine: lineIndex !== -1 ? lines[lineIndex].trim() : `$${varName}`,
+      lineNumber: i + 1,
+      matchedLine: trimmed,
       inferenceReason: reason,
     })
   }