feat(import): add shared Confluence margin-left indent normalizer

apps/server/src/integrations/import/utils/import-formatter.ts

@@ -97,8 +97,84 @@ export function xwikiFormatter($: CheerioAPI, $root: Cheerio<any>) {
   }
 }
 
+// Maximum indent level supported by the Indent editor extension (see
+// packages/editor-ext/src/lib/indent.ts). Values above this clamp down.
+const MAX_INDENT_LEVEL = 8;
+const MARGIN_LEFT_RE = /margin-left\s*:\s*(-?\d*\.?\d+)\s*px/i;
+const MARGIN_LEFT_STRIP_RE = /margin-left\s*:\s*-?\d*\.?\d+\s*px\s*;?/i;
+
+/**
+ * Confluence encodes paragraph indent as inline `style="margin-left: Npx"`.
+ * The per-level pixel value differs by edition: Cloud uses 30 (max 6 levels),
+ * Data Center uses 40 (no upper limit). The HTML-export ZIP path has no
+ * edition information available, so we auto-detect the per-level unit from
+ * the GCD of all margin-left values in the document. The API converter can
+ * pass `pxPerLevel` explicitly when the edition is known.
+ *
+ * Levels are written to `data-indent` for the TipTap Indent extension to
+ * pick up; the margin-left style is stripped from the element so the
+ * normalized indent doesn't double up with the editor's own indent padding.
+ */
+export function applyConfluenceMarginLeftIndent(
+  $: CheerioAPI,
+  $root: Cheerio<any>,
+  options?: { pxPerLevel?: number },
+): void {
+  const $els = $root.find('p, h1, h2, h3, h4, h5, h6');
+
+  const values: number[] = [];
+  $els.each((_, el) => {
+    const style = $(el).attr('style');
+    if (!style) return;
+    const match = MARGIN_LEFT_RE.exec(style);
+    if (!match) return;
+    const px = parseFloat(match[1]);
+    if (Number.isFinite(px) && px > 0) values.push(px);
+  });
+  if (values.length === 0) return;
+
+  const unit = options?.pxPerLevel ?? detectIndentUnit(values);
+  if (!unit || unit <= 0) return;
+
+  $els.each((_, el) => {
+    const $el = $(el);
+    const style = $el.attr('style');
+    if (!style) return;
+    const match = MARGIN_LEFT_RE.exec(style);
+    if (!match) return;
+    const px = parseFloat(match[1]);
+    if (!Number.isFinite(px) || px <= 0) return;
+    const level = Math.min(
+      MAX_INDENT_LEVEL,
+      Math.max(1, Math.round(px / unit)),
+    );
+    $el.attr('data-indent', String(level));
+    const remaining = style.replace(MARGIN_LEFT_STRIP_RE, '').trim();
+    if (remaining) {
+      $el.attr('style', remaining);
+    } else {
+      $el.removeAttr('style');
+    }
+  });
+}
+
+function detectIndentUnit(values: number[]): number {
+  // Confluence emits floats like "30.0"; round to ints for a clean GCD.
+  const ints = values.map((v) => Math.round(v)).filter((v) => v > 0);
+  if (ints.length === 0) return 0;
+  return ints.reduce((a, b) => gcd(a, b));
+}
+
+function gcd(a: number, b: number): number {
+  while (b !== 0) {
+    [a, b] = [b, a % b];
+  }
+  return a;
+}
+
 export function defaultHtmlFormatter($: CheerioAPI, $root: Cheerio<any>) {
   normalizeTableColumnWidths($, $root);
+  applyConfluenceMarginLeftIndent($, $root);
 
   $root.find('a[href]').each((_, el) => {
     const $el = $(el);