Fix 5 validator blockers in groups/users admin work

1. apps.ts getVisibleAppsForUser: use getEffectiveRoleIds() so admin
   gate honors group_roles inheritance (was direct user_roles only —
   security bypass for group-only admins). Exported helper from
   middlewares/auth.ts.

2. POST /users: switch from RegisterBody to new CreateUserBody schema
   that accepts optional groupIds[]. Validates ids exist; user creation
   + auto-Everyone + requested groups happen in single transaction.
   OpenAPI spec extended; api-zod and api-client-react regenerated.

3. DELETE /users/🆔 400 if req.session.userId === target (no
   self-delete).

4. scripts/src/seed.ts: removed `void inArray;` AI-slop and dropped
   unused inArray import.

5. Locales (ar.json + en.json): added admin.users.col.displayNameAr,
   displayNameEn, language and admin.groups.searchPlaceholder.

Typecheck clean. groups-crud + service-orders + users tests pass.
Pre-existing admin-app-opens-pagination flake unrelated.
Architect re-review: PASS.

lib/api-spec/openapi.yaml

@@ -1077,7 +1077,7 @@ paths:
         content:
           application/json:
             schema:
-              $ref: "#/components/schemas/RegisterBody"
+              $ref: "#/components/schemas/CreateUserBody"
       responses:
         "201":
           description: Created user
@@ -1584,6 +1584,32 @@ components:
         - email
         - password
 
+    CreateUserBody:
+      type: object
+      properties:
+        username:
+          type: string
+        email:
+          type: string
+        password:
+          type: string
+        displayNameAr:
+          type: ["string", "null"]
+        displayNameEn:
+          type: ["string", "null"]
+        preferredLanguage:
+          type: string
+          default: "ar"
+        groupIds:
+          type: array
+          description: Initial group memberships in addition to the auto-assigned Everyone group.
+          items:
+            type: integer
+      required:
+        - username
+        - email
+        - password
+
     LoginBody:
       type: object
       properties: