Paginate public v2 importmetadata and support descendants

[rtibbles]

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Overview

Studio's v2/importmetadata ignores max_results and descendants, and always returns the ancestors of one node as a single unpaginated dict. Since v0.19.3, Kolibri requests import metadata in pages and passes descendants for course imports. learningequality/kolibri#15352 makes Kolibri skip unpaginated sources for course imports, so until Studio supports both parameters, Kolibri can't import course metadata from Studio. Studio should paginate when given max_results and include descendants when given descendants, matching Kolibri's endpoint.

Complexity: Medium
Target branch: hotfixes

Context

• Kolibri's endpoint (import_metadata.py#L18-L205):
  • cursor pagination ordered by lft, with max_results as the page size;
  • a response of {"more": …, "results": {<table>: [...], "schema_version": …}};
  • descendants returns the ancestors plus all descendants, ordered by lft.
• Studio's current view: import_metadata_view.py#L69-L203

The Change

v2/importmetadata should accept max_results and descendants with the same semantics and response shape as Kolibri's endpoint. Without max_results, it keeps returning the unpaginated dict.

Acceptance Criteria

General

• With max_results=N, the response is {"more", "results"}, results holds the tables for at most N nodes, and requesting again with more as the query string returns the next page until more is null.
• With descendants=true, the paged results cover the node, its ancestors and all its descendants, in lft order, with no node repeated.
• Without max_results, the response is unchanged from today.
• Kolibri's _get_import_metadata imports a course node's metadata from Studio.

Testing

• Tests cover pagination with and without descendants, and the unpaginated response.

AI usage

I asked Claude Code to compare Kolibri's and Studio's v2 public content APIs. It found this gap and drafted the sections. I set the scope and target branch, and reviewed each section.

[rtibblesbot]

Plan: v2/importmetadata paginates on max_results and includes descendants on descendants, matching Kolibri's endpoint.

• Paginate on max_results
• Include descendants on descendants
• Self-review the produced code

Assumptions — the issue did not settle these; say so if one is wrong.

• descendants is on for any non-empty value, as Kolibri's if descendants:. If descendants=false must mean off, compare to "true".
• There is no page-size cap, as in Kolibri and publiccontentnode-list. If Studio needs one, set max_page_size on ImportMetadataPagination.
• Prerequisite and related rows whose ends land on different pages are dropped, as in Kolibri. If Kolibri needs them, both endpoints change.
• AC4 runs Kolibri #15352's _get_import_metadata against a local Studio seeded by ChannelBuilder. If it needs a published channel, QA repeats the check on a deployed Studio.

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@rtibblesbot's comments are generated by an LLM, and should be evaluated accordingly

How was this generated?

• Implemented code following the pre-approved plan using test-driven development (red-green-refactor)
• Ran the project's full test suite and linter before committing
• For UI changes: captured live screenshots to verify rendering
• For backend changes: verified with example API/CLI output