refactor(admin-web): move answer markdown normalization to a tested lib

Extract normalizeLooseMarkdownLine from TrackingQuestionDetailView into
a shared monitoring-answer-markdown module and harden it (model bullet
`**-` and `*` handling). Add a vitest runner and unit tests for the
normalization rules.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/admin-web/src/views/TrackingQuestionDetailView.vue

@@ -17,6 +17,7 @@ import MarkdownPreview from '@/components/MarkdownPreview.vue'
 import { monitoringApi } from '@/lib/api'
 import { formatDateTime } from '@/lib/display'
 import { formatError } from '@/lib/errors'
+import { normalizeLooseMarkdownLine } from '@/lib/monitoring-answer-markdown'
 import { isMonitoringPlatformId, normalizeMonitoringPlatformId } from '@/lib/monitoring-platforms'
 import { useCompanyStore } from '@/stores/company'
 
@@ -790,23 +791,6 @@ function sanitizeAnswerBody(answerText: string | null | undefined): string | nul
   return sanitized || null
 }
 
-function normalizeLooseMarkdownLine(line: string): string {
-  const headingNormalizedLine = line
-    .replace(/^[\u200b-\u200f\ufeff]+/, '')
-    .replace(/^([ \t]{0,12})(?:\\#|#|#|＃)/i, '$1#')
-  const answerScopedHeading = headingNormalizedLine.replace(
-    /^([ \t]{0,12})#{1,2}(?!#)\s*(?=\S)/,
-    '$1### ',
-  )
-
-  return answerScopedHeading
-    .replace(/^([ \t]{0,12})(#{1,6})(?=\S)/, '$1$2 ')
-    .replace(/^([ \t]{0,12}#{1,6}\s+)#{1,6}\s*/, '$1')
-    .replace(/^([ \t]{0,12}#{1,6}\s+\d+[.)、])(?=\S)/, '$1 ')
-    .replace(/^(\s*)([-*+])(?=\S)/, '$1$2 ')
-    .replace(/^(\s*)(\d{1,3})([.)])(?=\S)/, '$1$2$3 ')
-}
-
 function countMarkdownTablePipes(line: string): number {
   return (line.match(/\|/g) ?? []).length
 }