Duo Chat: Map "directory" category to repository FF

What does this MR do and why?

As part of Semantic search: chat with your codebase (&16910), we introduced a new functionality in Duo Chat that allows the user to include a directory as an additional context category through the /include directory menu.

This was implemented in #548423 (closed) (Rails) and gitlab-org/editor-extensions/gitlab-lsp#1098 (closed) (Language Server), with the "directory" category being toggled by the duo_include_context_repository Feature Flag. However, we have discovered that this was not yet mapped correctly (see "Error details" section below).

To fix this, we need to ensure that the new directory category is mapped to the duo_include_context_repository Feature Flag.

Error details

&17300 (comment 2705479480):

/include directories has an error

References

Related issue: [LS/Backend] Map 'directory' category to 'repos... (gitlab-org/editor-extensions/gitlab-lsp#1386 - closed)

Screenshots or screen recordings

N/A - see local validation

How to set up and validate locally

1. Make sure that you have a project with Code Embeddings, see #550418 (comment 2610944159)

2. Enable duo_include_context_repository Feature Flag

3. On Duo Chat, use the /include directory menu and verify that you did not run into the error shown in "Error details" above.

   Note: the Duo Chat answer here is incorrect, but this is unrelated to the category<->FF mapping issue. The important thing to note is that there were no errors that popped up.

   

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