Duplicate heading ids generated for headings repeated 3+ times

[vdvman1]

parseHeader in src/components/java/patch-notes.tsx de-duplicates generated heading ids, but writes the counter under the already-suffixed id instead of the base id:

let id = toKebabCase(headingText);
const dups = ids.get(id) ?? 0;
if (dups > 0) {
  id += `-${dups}`;
}
ids.set(id, dups + 1);   // <-- `id` has already been reassigned

So the base id's counter never advances past 1:

occurrence	dups read	id emitted	counter written
1st	0 (parameters)	parameters	parameters → 1
2nd	1 (parameters)	parameters-1	parameters-1 → 2
3rd	1 (parameters)	parameters-1	parameters-1 → 2

Every occurrence from the third onward collides on -1.

Impact. Duplicate DOM ids, so the table-of-contents anchor links for the affected headings all jump to the same place. Measured across all 403 articles in the v2 manifest: 7 articles emit literally duplicate ids, worst case 1.14, which emits parameters-1 ten times.

Fix. Key the counter on the base id:

const base = toKebabCase(headingText);
const dups = ids.get(base) ?? 0;
const id = dups > 0 ? `${base}-${dups}` : base;
ids.set(base, dups + 1);

Note this still can't guarantee uniqueness against a heading whose literal text is Parameters 1, so consider a uniqueness check on the final id.

Found while researching #36 (annotation anchoring) — heading-derived ids were being evaluated as an anchor selector and rejected partly because of this. Filing separately because it is a live bug in the rendered page today, independent of that work.