Support for sticky items, basic article content in the item payload

[IvanJelicSF]

Summary

Adds three related capabilities to the content-lists bulk-patch flow:

1. Sticky flag on move. The move action now reads and writes the sticky field, so items can be pinned or unpinned in the same call that repositions them. When sticky is omitted the existing value is preserved.
2. Article content in list-item responses. GET responses for /content_lists/<id>/items are enriched with an article_content object (title, state, thumbnail) for every item. The thumbnail prefers the feature-media thumbnail rendition and falls back to the first <img> in body_html.
3. Unique positions after every batch. A new _renumber step runs after each bulk patch and re-assigns positions so that every item has a unique slot. Sticky items and items touched by the current batch (add / move) anchor at their declared position; untouched non-sticky items fill the lowest free slots in their previous order. If two anchors collide, sticky wins, then the most recently touched within a group, with the loser spilling to the next free slot.

Files changed

File	Change
apps/content_lists/article_content.py	New. Async enrichment helpers (attach_article_content, enrich_fetched_response, enrich_fetched_item) and thumbnail extraction.
apps/content_lists/rest_endpoints.py	Wires on_fetched / on_fetched_item to the new enrichment hooks.
apps/content_lists/service.py	move reads/writes sticky; tracks touched items; calls new _renumber to keep positions unique via a single bulk UpdateOne write.
features/content_lists.feature	Six new BDD scenarios covering sticky toggling, sticky preservation, position shifting on move/add, position shifting on delete, and the higher-position move case.

Diffstat: 4 files changed, 397 insertions(+), 2 deletions(-)

Commits

• 97ce1273 Update positions of other items affected by moving/adding/removing
• 9cc14271 Adding article info to the list items response
• 2b9acd71 Enable sticky read/write for the move action
• 55520b25 Sync enable sticky read/write for the move action with latest changes
• 1f19b058 Merge PR fixed setup.py, removed source folder #1 (sticky)
• 106a75d8 Merge PR [SD-3031] Updates of images from Reuters causes media entries to beco… #2 (article data)
• 4fc2e2dd Keep list positions unique by anchoring sticky and moved items

Behaviour notes

• _renumber is a no-op when nothing needs to change — only positions that actually shift are written, via a single bulk_write(ordered=False).
• move without an explicit sticky keeps the previous value (verified by Move action preserves sticky flag when not provided).
• article_content is None for items whose archive document cannot be found, so the field is always present in responses.
• Thumbnail lookup never raises — parse_html failures degrade silently to None.

Test plan

• Run features/content_lists.feature — all six new scenarios should pass alongside the existing ones.
• GET /content_lists/<id>/items returns article_content for items whose archive document exists, and null otherwise.
• move with sticky: true pins an item; subsequent move with sticky: false unpins it.
• Adding/moving items into occupied positions shifts neighbours so positions remain unique and contiguous from 0.
• Deleting an item closes the gap (no holes in the position sequence).
• Sticky items keep their declared position when other items are added, moved, or deleted around them.

Resolves: SDESK-7929 SDESK-7935