fix(endpoint-syndicate): retry targets a post has not syndicated to yet

[rmdes]

Fixes #896.

   const items = await postsCollection
     .find({
       "properties.mp-syndicate-to": {
         $exists: true,
       },
-      "properties.syndication": {
-        $exists: false,
-      },
       "properties.post-status": {
         $ne: "draft",
       },
     })

The removed condition excluded any post that had ever been syndicated anywhere, which after a partial run is the post that still has targets outstanding: the controller replaces mp-syndicate-to with the failed targets and sets syndication to the URLs that worked, so the post holds both properties and is never selected again.

Why removing it is safe

It reads like a guard against re-syndicating finished posts, but two things already cover that:

• a post whose targets have all returned a URL has mp-syndicate-to deleted by the same controller, so it stops matching the first condition;
• syndicateToTargets calls hasSyndicationUrl per target, so a post selected again is not re-syndicated to a target it already reached.

I added a comment at the query recording that, since the reasoning lives in another file.

Test

One unit test in test/unit/utils.js, for a post holding mp-syndicate-to and syndication together. It fails on main and passes with this change. It uses its own collection so it cannot be confused with the shared fixture.

node --test test/unit/utils.js: 7 passing. Package-wide: 24 tests, 24 passing; 23/23 on main before this change.

I checked that no existing test depended on the removed condition: 200-no-posts-awaiting-syndication.js posts an entry with no mp-syndicate-to at all, so the first condition already excludes it.

Relationship to #895

Both change lib/utils.js and test/unit/utils.js, but different functions and different tests. I merged the two branches locally to check rather than assume: they auto-merge with no conflict, and the combined result gives 25 tests, 25 passing package-wide. Either order should be fine.

[paulrobertlloyd]

Not sure why I added that condition and yes, in retrospect, it doesn’t appear necessary.