feat: manage OS images in database instead of hardcoded values

- Add os_images table with linode_image_id and vultr_os_id columns
- Support Ubuntu (24.04, 22.04), Debian (11-13), AlmaLinux (8-9),
  Rocky Linux (8-9), and Fedora 42
- AlmaLinux and Rocky Linux added as CentOS migration alternatives
- Default OS changed from ubuntu_22_04 to ubuntu_24_04
- Fix Vultr OS IDs (1743=22.04, 2284=24.04)
- Remove hardcoded OS validation, validate against DB
- Return available OS list in error message for invalid image

Migration: migrations/003_os_images.sql

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/repositories/ProvisioningRepository.ts

@@ -5,7 +5,7 @@
  * - USER_DB (telegram-conversations): users, deposits, orders
  */
 
-import type { TelegramUser, UserDeposit, ServerOrder, PricingWithProvider } from '../types';
+import type { TelegramUser, UserDeposit, ServerOrder, PricingWithProvider, OsImage } from '../types';
 
 export class ProvisioningRepository {
   constructor(
@@ -276,4 +276,58 @@ export class ProvisioningRepository {
     await this.refundBalance(userId, amount);
     await this.updateOrderStatus(orderId, 'failed', errorMessage);
   }
+
+  // ============================================
+  // OS Image Operations (cloud-instances-db.os_images)
+  // ============================================
+
+  /**
+   * Get all active OS images
+   */
+  async getActiveOsImages(): Promise<OsImage[]> {
+    const result = await this.db
+      .prepare(
+        `SELECT * FROM os_images
+         WHERE active = 1
+         ORDER BY sort_order`
+      )
+      .all();
+
+    return result.results as unknown as OsImage[];
+  }
+
+  /**
+   * Get OS image by key
+   */
+  async getOsImageByKey(key: string): Promise<OsImage | null> {
+    const result = await this.db
+      .prepare('SELECT * FROM os_images WHERE key = ? AND active = 1')
+      .bind(key)
+      .first();
+
+    return result as unknown as OsImage | null;
+  }
+
+  /**
+   * Get default OS image
+   */
+  async getDefaultOsImage(): Promise<OsImage | null> {
+    const result = await this.db
+      .prepare('SELECT * FROM os_images WHERE is_default = 1 AND active = 1')
+      .first();
+
+    return result as unknown as OsImage | null;
+  }
+
+  /**
+   * Validate OS image key exists and is active
+   */
+  async isValidOsImage(key: string): Promise<boolean> {
+    const result = await this.db
+      .prepare('SELECT 1 FROM os_images WHERE key = ? AND active = 1')
+      .bind(key)
+      .first();
+
+    return result !== null;
+  }
 }