chore: add user details to aibridge interception list endpoint (#20397)

- Adds FK from `aibridge_interceptions.initiator_id` to `users.id`
- This is enforced by deleting any rows that don't have any users. Since
this is an experimental feature AND coder never deletes user rows I
think this is acceptable.
- Adds `name` as a property on `codersdk.MinimalUser`
- This matches the `visible_users` view in the database. I'm unsure why
`name` wasn't already included given that `username` is.
- Adds a new `initiator` field to `codersdk.AIBridgeInterception` which
contains `codersdk.MinimalUser` (ID, username, name, avatar URL)
- Removes `initiator_id` from `codersdk.AIBridgeInterception`
    - Should be fine since we're still in early access

docs/reference/api/workspaces.md

@@ -1588,6 +1588,7 @@ curl -X GET http://coder-server:8080/api/v2/workspaces/{workspace}/acl \
     {
       "avatar_url": "http://example.com",
       "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",
+      "name": "string",
       "role": "admin",
       "username": "string"
     }