Update user deletion to reassign roles and fix foreign key constraint violations

Update the deleteUser function in DatabaseStorage to reassign roles assigned by the deleted user to the admin user, resolving a foreign key constraint error when deleting the 'system' user.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: a8a78c07-e900-425c-a577-5b4c5894379d
Replit-Commit-Checkpoint-Type: full_checkpoint
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attached_assets/Pasted-GET-api-users-200-in-33ms-Error-deleting-user-error-update-or-delete-on-table-users-violates-1754935124372_1754935124372.txt

@@ -0,0 +1,108 @@
+GET /api/users 200 in 33ms
+
+Error deleting user: error: update or delete on table "users" violates foreign key constraint "user_roles_assigned_by_fkey" on table "user_roles"
+
+    at /app/node_modules/pg/lib/client.js:545:17
+
+    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
+
+    at async file:///app/dist/index.js:1108:11
+
+    at async NodePgSession.transaction (file:///app/node_modules/drizzle-orm/node-postgres/session.js:142:22)
+
+    at async DatabaseStorage.deleteUser (file:///app/dist/index.js:1090:9)
+
+    at async file:///app/dist/index.js:4094:7 {
+
+  length: 299,
+
+  severity: 'ERROR',
+
+  code: '23503',
+
+  detail: 'Key (id)=(system) is still referenced from table "user_roles".',
+
+  hint: undefined,
+
+  position: undefined,
+
+  internalPosition: undefined,
+
+  internalQuery: undefined,
+
+  where: undefined,
+
+  schema: 'public',
+
+  table: 'user_roles',
+
+  column: undefined,
+
+  dataType: undefined,
+
+  constraint: 'user_roles_assigned_by_fkey',
+
+  file: 'ri_triggers.c',
+
+  line: '2609',
+
+  routine: 'ri_ReportViolation'
+
+}
+
+DELETE /api/users/system 500 in 29ms
+
+HEAD /api/health 200 in 1ms
+
+Error deleting user: error: update or delete on table "users" violates foreign key constraint "user_roles_assigned_by_fkey" on table "user_roles"
+
+    at /app/node_modules/pg/lib/client.js:545:17
+
+    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
+
+    at async file:///app/dist/index.js:1108:11
+
+    at async NodePgSession.transaction (file:///app/node_modules/drizzle-orm/node-postgres/session.js:142:22)
+
+    at async DatabaseStorage.deleteUser (file:///app/dist/index.js:1090:9)
+
+    at async file:///app/dist/index.js:4094:7 {
+
+  length: 299,
+
+  severity: 'ERROR',
+
+  code: '23503',
+
+  detail: 'Key (id)=(system) is still referenced from table "user_roles".',
+
+  hint: undefined,
+
+  position: undefined,
+
+  internalPosition: undefined,
+
+  internalQuery: undefined,
+
+  where: undefined,
+
+  schema: 'public',
+
+  table: 'user_roles',
+
+  column: undefined,
+
+  dataType: undefined,
+
+  constraint: 'user_roles_assigned_by_fkey',
+
+  file: 'ri_triggers.c',
+
+  line: '2609',
+
+  routine: 'ri_ReportViolation'
+
+}
+
+DELETE /api/users/system 500 in 19ms
+