Add Feature Library modal scaffold to super sidebar
NOTE: This is based off mock data when #601393 and other enrichments are done, we can remove the mock data.
Here are the things which will change:
remove: mock_catalog.js
Partially constants.js as well.
What does this MR do?
Adds a feature-flag-gated Feature Library modal to the super sidebar. A "Browse more features" trigger opens a modal where users can search features, filter by category tab, and pin them. Pinning reuses the existing super sidebar pin flow.
The catalog is currently a client-side mock fixture, pruned so every entry's item_id resolves to a real, pinnable nav item in its declared panel — pinning always lands on a working resource. It will be replaced by server-driven data in the follow-up issue below.
Gated behind the default-off feature_library_modal flag, so it is not user-visible until the flag is enabled.
Screenshots / screen recordings
Behind a default-off flag. UI mirrors the demo app at https://nav-gem-a6866e.gitlab.io.
Before:
No Browse New Features:
| desktop | mobile | expanded | collapsed |
|---|---|---|---|
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 |
 |
 |
How to set up and validate locally
Feature.enable(:feature_library_modal)in the Rails console.- Open a project (or group) sidebar while logged in — the "Browse more features" trigger appears in the pinnable section.
- Open it, search/filter, and pin/unpin items.
References
- Feature issue: #601394 (closed)
- Server-driven catalog follow-up: #601393
- Epic: gitlab-org#20545