Update system name and references from TeaBoy to Tx

Replaces all user-facing instances of "TeaBoy" with "Tx" across the application, including titles, locale files, database settings, seed data, and API documentation. Also updates internal storage keys and session secrets to remove the old branding.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 77cfe984-2c65-4152-bb7a-0df28274fe66
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 07b19cb0-11b5-4be9-8932-ae4820eb73b8
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Replit-Helium-Checkpoint-Created: true

lib/db/src/schema/settings.ts

@@ -4,8 +4,8 @@ import { z } from "zod/v4";
 
 export const appSettingsTable = pgTable("app_settings", {
   id: integer("id").primaryKey().default(1),
-  siteNameAr: varchar("site_name_ar", { length: 200 }).notNull().default("نظام TeaBoy"),
-  siteNameEn: varchar("site_name_en", { length: 200 }).notNull().default("TeaBoy OS"),
+  siteNameAr: varchar("site_name_ar", { length: 200 }).notNull().default("نظام Tx"),
+  siteNameEn: varchar("site_name_en", { length: 200 }).notNull().default("Tx OS"),
   registrationOpen: boolean("registration_open").notNull().default(true),
   footerTextAr: varchar("footer_text_ar", { length: 300 }).notNull().default("جميع الحقوق محفوظة."),
   footerTextEn: varchar("footer_text_en", { length: 300 }).notNull().default("All rights reserved."),