Reduce repeated favorite queries while serializing API v3 project collections.

[haseebeqx]

Serializing GET /api/v3/projects calls Project#favorited_by? while building each project’s favorite links and favorited property. This resulted in a separate favorite existence query for every project in the collection.

In the profiled workload, 50 favorite existence queries were issued for a page containing 50+ projects.

Changes

1. The project collection eager-loading wrapper now loads the current user’s favorite project IDs in one query for the complete page.
2. favorited_by? uses the preloaded value when called for that user. Calls for another user, or without preloaded
   data, continue to delegate to the underlying project model.
3. The project collection representer now always invokes its project-specific eager-loading wrapper and passes the
   current user to it.
4. The offset-paginated collection makes the current user available while paginated records are being prepared.
5. Added tests covering bulk loading, favorite-state accuracy, fallback behavior for other users, and collection integration.

Performance

Measured in production mode against:

GET /api/v3/projects?pageSize=50&offset=1

The dataset contained 62 active projects, with 50 returned per request. The observed values are medians from five runs per state in a local environment using a system-admin API key

Metric	Before	After	Change
Median server duration	139.49 ms	89.86 ms	-35.6%
Median SQL duration	16.18 ms	5.76 ms	-64.4%
SQL events	58	9	-84.5%
Non-cached SQL events	58	9	-84.5%
Duplicate query fingerprints	49	0	-100.0%
Per-project favorite existence checks	50	0	-100.0%

Merge checklist

• Added/updated tests
• Added/updated documentation in Lookbook (patterns, previews, etc)
• Tested major browsers (Chrome, Firefox, Edge, ...)

[haseebeqx]

Project loading uses custom wrapper logic beyond the representer’s declarative Rails eager-load configuration. Returning true ensures that wrapper always runs for the paginated project relation.

[haseebeqx]

@oliverguenther Please review