Read the quizzes behind H5P elements

A quiz in Schulcloud is an H5P element, and a board hands over nothing but a
contentId — so a teacher's exercise was until now a line saying one exists.
The player shows a single question at a time, which makes it look like
something to step through or scrape. It is not:
`GET /api/v3/h5p-editor/params/{contentId}` returns the JSON the player is fed,
so one request holds every question, every option and which of them are
correct. (`play/{id}` is the same content plus the player's script lists: 74 kB
against 51 kB for the live quiz. Neither docs-json describes the service.)

get_h5p prints the exercise, and solutions=false keeps the options while
dropping the answers, so it can be used to ask the questions instead of
answering them. get_board names the exercise — title, question count, kinds —
rather than printing a bare id, and the crawl indexes its text, so a phrase
that exists only inside a quiz is now findable. That is the treatment pads
already get, for the same reason: it is course material and nothing else
surfaces it.

What varies is the shape inside `params`, which belongs to whichever H5P
library the teacher used. Modelled: MultiChoice, whose `behaviour.singleAnswer`
is the only honest source for "tick exactly one"; TrueFalse, whose `correct` is
the string "true"; the cloze libraries, which mark solutions inline as
`*answer:tip*`; SingleChoiceSet and Summary, which put the correct option first
and let the player shuffle; and Column. Anything else has its text harvested
and labelled unmodelled — an exercise reported as "0 questions" would be worse
than a clumsy rendering of one. The harvest skips the UI and l10n subtrees, or
a quiz reads as "Überprüfen, Wiederholen, Absenden".

Verified against this account's quiz, an H5P.QuestionSet of 20 MultiChoice
questions on a room's board: 239 tests, smoke 91/91 live-only and 93/93 with
the index.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/core/client.ts

@@ -450,6 +450,21 @@ export class SchulcloudClient {
 		return this.getJson<BoardContext>(`/api/v3/boards/${encodeURIComponent(boardId)}/context`);
 	}
 
+	/**
+	 * The content behind an H5P element: a quiz with all of its questions.
+	 *
+	 * `params` is what the player loads before it renders anything, so one GET
+	 * returns the whole exercise — every question, every answer option and which
+	 * of them is correct — even though the player then shows one question at a
+	 * time. There is nothing to step through and no page to scrape.
+	 *
+	 * The shape belongs to whichever H5P library the content uses, so it stays
+	 * `unknown` here and `core/h5p.ts` interprets it.
+	 */
+	getH5pParams(contentId: string): Promise<unknown> {
+		return this.getJson<unknown>(`/api/v3/h5p-editor/params/${encodeURIComponent(contentId)}`);
+	}
+
 	/**
 	 * Card bodies for the given ids.
 	 *