feat(labs): let a person order the lab categories (#1349)

The labs list layout gains categoryOrder, a bounded allow-list of
category keys (200 entries, 64 characters each, deduplicated, malformed
values dropped on read). GET /api/labs/overview reads the caller's own
layout and answers categories already in that order, so every client
renders them as given. Listed categories come first; keys the data does
not have are ignored; a category the order does not name follows in
the default order (catalog panels, then the person's own by label, then
other). Other left at the end of the order stays last, behind any
category added later; moved anywhere else, it stays there.

Settings > Arrangement > Labs shows a category order card while
categories are on. It lists the overview's categories under their
localised labels, sends the whole order after every move, moves the
cached overview at once and refetches it. The card says how the default
order works. The OpenAPI document carries the new field.

docs/api/openapi.yaml

@@ -34362,6 +34362,13 @@ components:
             - expanded
             - flagged
             - collapsed
+        categoryOrder:
+          maxItems: 200
+          type: array
+          items:
+            type: string
+            minLength: 1
+            maxLength: 64
       required:
         - version
         - list
@@ -75520,6 +75527,15 @@ components:
             - collapsed
           description: 'Which labs categories start open: every one (`expanded`), only those whose `status` is `above` or `below`
             (`flagged`), or none (`collapsed`). Default "expanded". The other lists ignore it.'
+        categoryOrder:
+          type: array
+          items:
+            type: string
+          description: The person's order of the labs categories, as `categories[].key` values of `GET /api/labs/overview`. The
+            server applies it there, so a client renders `categories` as given and never sorts them itself. Keys missing
+            from the live data are ignored; a category missing from the list follows the listed ones in the default
+            order, and "other" left at the end of the list stays last. Default empty (the default order). The other
+            lists ignore it.
         saved:
           type: boolean
           description: True when the server holds a choice for this list; false means every field is a default.
@@ -75529,6 +75545,7 @@ components:
         - sortDir
         - groupBy
         - groupsOpen
+        - categoryOrder
         - saved
       additionalProperties: false
     ModuleListLayoutSavedEnvelope:
@@ -77121,8 +77138,10 @@ components:
           type: array
           items:
             $ref: "#/components/schemas/LabOverviewCategory"
-          description: "The list's categories in display order: catalog panels in catalog order, then the person's own panels by
-            label, then `other`."
+          description: "The list's categories in display order, already arranged for the caller: the default order is catalog
+            panels in catalog order, then the person's own panels by label, then `other`, and the caller's
+            `categoryOrder` (`PUT /api/settings/module-list-layout`, labs list) is applied over it. Render them in this
+            order."
         grouped:
           type: boolean
           description: "Whether grouping adds anything: true when there are two categories or more and at least one is not