…presets (#20493)The membership reconciliation ensures the prebuilds system user is amember of all organizations with prebuilds configured. To supportprebuilds quota management, each organization must have a prebuildsgroup that the system user belongs to.Previously, membership reconciliation iterated over all presets to checkand update membership status. This meant database queries`GetGroupByOrgAndName` and `InsertGroupMember` were executed for eachpreset. Since presets are unique combinations of `(organization,template, template version, preset)`, this resulted in several redundantchecks for the same organization.In dogfood, `InsertGroupMember` was called thousands of times per day,even though memberships were already configured ([internal Grafanadashboard link](https://grafana.dev.coder.com/goto/46MZ1UgDg?orgId=1))<img width="5382" height="1788" alt="Screenshot 2025-10-28 at 16 01 36"src="https://github.com/user-attachments/assets/757b7253-106f-4f72-8586-8e2ede9f18db"/>This PR introduces `GetOrganizationsWithPrebuildStatus`, a single querythat returns:* All unique organizations with prebuilds configured* Whether the prebuilds user is a member of each organization* Whether the prebuilds group exists in each organization* Whether the prebuilds user is in the prebuilds groupThe membership reconciliation logic now:* Fetches status for all organizations in one query* Only performs inserts for organizations missing required membershipsor groups* Safely handles concurrent operations via unique constraint violations* This reduces database load from `O(presets)` to `O(organizations)` perreconciliation loop, with a single read query when everything isconfigured.* Add `GetOrganizationsWithPrebuildStatus` SQL query* Update `membership.ReconcileAll` to use organization-basedreconciliation instead of preset-based* Update tests to reflect new behaviorRelated to internal thread:https://codercom.slack.com/archives/C07GRNNRW03/p1760535570381369(cherry picked from commit7e8fcb4)