fix(council): handle whitespace around COUNCIL_MEMBER_RESPONSE tags

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/council-archive/council-response-extractor.ts

@@ -55,12 +55,20 @@ export function hasCouncilResponseTag(sessionMessages: Array<{ info?: { role?: s
 }
 
 function isStructuralOpen(text: string, idx: number): boolean {
-  return idx === 0 || text[idx - 1] === "\n"
+  if (idx === 0) return true
+  const prevNewline = text.lastIndexOf("\n", idx - 1)
+  const lineStart = prevNewline === -1 ? 0 : prevNewline + 1
+  const between = text.slice(lineStart, idx)
+  return between.split("").every((ch) => ch === " " || ch === "\t")
 }
 
 function isStructuralClose(text: string, idx: number): boolean {
   const afterIdx = idx + CLOSING_TAG.length
-  return afterIdx === text.length || text[afterIdx] === "\n" || text[afterIdx] === "\r"
+  if (afterIdx === text.length) return true
+  const nextNewline = text.indexOf("\n", afterIdx)
+  const lineEnd = nextNewline === -1 ? text.length : nextNewline
+  const between = text.slice(afterIdx, lineEnd)
+  return between.split("").every((ch) => ch === " " || ch === "\t" || ch === "\r")
 }
 
 function findLastStructuralClose(text: string): number {