Add the tech-categories collection that gives technologies a home off the
flat uncategorized pool, plus the schema support the admin editor needs.
- New `tech-categories` collection (unique name, timeline `position`,
optional hex `color`) with a `Technologies.category` FK (ON DELETE set
null) so deleting a category just unfiles its technologies.
- Add `Technologies.treePosition {x,y}` so the canvas can pin a node's
manual position; clearing it uses `{x:null,y:null}`.
- Register the two hand-written migrations (tech-categories + treePosition)
and regenerate payload-types, the drizzle schema, and the admin importMap.
- Register the `tech-categories:*` permission group and grant Intelligence
division members admin-panel access, mirroring technologies.
