Add GitLab as Known Instance across two patterns

Based on Raimund Hook's InnerSource Commons talk "Break the contribution
wall" (April 2026), GitLab's DevRel Engineering team's contributor-growth
program is added as a Known Instance to:

- Incentive Mechanisms for Voluntary Contributions: contributors.gitlab.com
  gamifies contribution across code, review, docs, and translations with
  points, levels, and leaderboards, unlocking exclusive contributor swag -
  replaces "TBD" Known Instances
- Internal Developer Platform: GitLab containerized their GDK, cutting
  new-contributor environment setup from ~2 hours (often failing) to
  under 5 minutes

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

Author: rrrutledge

patterns/1-initial/incentive-mechanisms-for-voluntary-contribution.md

@@ -116,7 +116,7 @@ This approach targets key human motivators for voluntary participation: financia
 
 ## Known Instances
 
-TBD
+* **GitLab** - GitLab's DevRel Engineering team built [contributors.gitlab.com](https://contributors.gitlab.com), a platform that gamifies contribution across code, code review, documentation, and translations with points, levels, and leaderboards. Points unlock access to exclusive contributor-only swag, redeemable only through sustained contribution. See: [Break the contribution wall](https://www.youtube.com/watch?v=d3igPlTr4Ag) (InnerSource Commons, 2026, by Raimund Hook).
 
 ## Status
 

patterns/1-initial/internal-developer-platform.md

@@ -123,7 +123,7 @@ An IDP provides a solution to the competing forces of consistency, flexibility,
 
 ## Known Instances
 
-(known instances to be added)
+* **GitLab** - GitLab containerized their GitLab Development Kit (GDK), cutting new-contributor environment setup from roughly two hours (frequently failing) to under five minutes. This directly reduced time-to-first-contribution for both open source and InnerSource-style contributors. See: [Break the contribution wall](https://www.youtube.com/watch?v=d3igPlTr4Ag) (InnerSource Commons, 2026, by Raimund Hook).
 
 ## Status