/rest/v1/tags and db.get_by_tags() return unbounded results — pagination TODO never implemented #1087

What is the issue?

GET /rest/v1/tags (find_document_by_tag in application/web/web_main.py) calls db.get_by_tags(tags), which runs two unbounded queries:

Node.query.filter(*nodes_where_clause).all()
CRE.query.filter(*cre_where_clause).all()

Neither has a LIMIT. Both the route and the DB method carry an explicit TODO from the pagination never having been implemented:

• application/web/web_main.py:300 — # TODO: (spyros) paginate
• application/database/db.py:1615 — # TODO: (spyros), when we have useful tags this needs to be refactored so both standards and CREs become the same query and it gets paginated

A tag matched by many nodes/CREs (tag matching is a LIKE "%tag%" substring match, so even a short/common tag string can match broadly) returns every matching row in one response — unbounded response size on a public endpoint.

Expected behaviour

/rest/v1/tags should support the same page / items_per_page query params as the sibling /rest/v1/id/... route, bounded by the existing
ITEMS_PER_PAGE (20) / MAX_ITEMS_PER_PAGE (100) constants.

Proposed solution

Add get_by_tags_with_pagination() alongside the existing get_by_tags() (same pattern as get_nodes() / get_nodes_with_pagination() already in db.py), so non-paginated callers (e.g. line 109's internal tag-linking use) are unaffected.

Design decision: get_by_tags combines two separate queries (Node, CRE) into one list, so a single .paginate() call (as used in get_nodes_with_pagination) doesn't map directly onto it. Proposed v1: paginate the Node and CRE queries independently with the same
page/items_per_page, and return them as two labeled lists rather than one merged list:

{"nodes": {...}, "cres": {...}, "page": ..., "total_pages": ...}

This keeps each query's pagination correct and avoids manual offset math across heterogeneous result sets. Happy to adjust if a merged/interleaved result is preferred.

CSV/Markdown/OSCAL export formats (opt_format) would keep using the existing unpaginated get_by_tags(), matching how /rest/v1/id/... already treats exports as an unpaginated special case.

Acceptance criteria

• /rest/v1/tags accepts page / items_per_page, bounded by MAX_ITEMS_PER_PAGE.
• Export formats (CSV/Markdown/OSCAL) unaffected.
• New tests in db_test.py / web_main_test.py covering pagination boundaries (page 1, last page, page beyond range, custom items_per_page).
• Existing test_get_by_tags / test_find_document_by_tag still pass unmodified (backward compatible for non-paginated callers).
• make lint / make mypy / make test green.

I'd like to work on this