[Index state tracking: Rollout] GitLab.com

Description

This issue tracks the rollout of the Codebase Semantic Search feature to GitLab.com. This feature provides an additional context category for GitLab Duo Chat, allowing users to include repository context in their chat interactions. Chat with your codebase.

This is an additional context category within the existing GitLab Duo Chat functionality. It's controlled by the duo_include_context_repository feature flag on the frontend and gated by the chat Duo licenses.

The feature has already been rolled out to the gitlab-org group #555560 (closed) and is now ready for broader GitLab.com deployment.

We need to review the code related to the reindexing and update the namespace logic.