Ship legacy migrate APIs, portfolio/blog old-id schema, and admin migrate/purge flows.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/legacy-mysql/legacy-mysql.service.ts

@@ -0,0 +1,71 @@
+import {
+  Injectable,
+  OnModuleDestroy,
+  ServiceUnavailableException,
+} from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import mysql, { Pool, PoolOptions, RowDataPacket } from 'mysql2/promise';
+
+@Injectable()
+export class LegacyMysqlService implements OnModuleDestroy {
+  private pool: Pool | null = null;
+
+  constructor(private readonly config: ConfigService) {}
+
+  async onModuleDestroy() {
+    if (this.pool) {
+      await this.pool.end();
+      this.pool = null;
+    }
+  }
+
+  isConfigured(): boolean {
+    return Boolean(
+      this.config.get<string>('OLD_MYSQL_HOST') &&
+        this.config.get<string>('OLD_MYSQL_USER') &&
+        this.config.get<string>('OLD_MYSQL_DATABASE'),
+    );
+  }
+
+  async query<T extends RowDataPacket[]>(
+    sql: string,
+    params: unknown[] = [],
+  ): Promise<T> {
+    const pool = this.getPool();
+    try {
+      const [rows] = await pool.query<T>(sql, params);
+      return rows;
+    } catch (err) {
+      const message = err instanceof Error ? err.message : 'Unknown MySQL error';
+      throw new ServiceUnavailableException(
+        `Old CMS MySQL query failed: ${message}. Ensure the SSH tunnel is up and OLD_MYSQL_* is set.`,
+      );
+    }
+  }
+
+  private getPool(): Pool {
+    if (this.pool) {
+      return this.pool;
+    }
+
+    if (!this.isConfigured()) {
+      throw new ServiceUnavailableException(
+        'Old CMS MySQL is not configured. Set OLD_MYSQL_HOST, OLD_MYSQL_USER, OLD_MYSQL_DATABASE (and password/port).',
+      );
+    }
+
+    const options: PoolOptions = {
+      host: this.config.getOrThrow<string>('OLD_MYSQL_HOST'),
+      port: Number(this.config.get<string>('OLD_MYSQL_PORT', '3307')),
+      user: this.config.getOrThrow<string>('OLD_MYSQL_USER'),
+      password: this.config.get<string>('OLD_MYSQL_PASSWORD', ''),
+      database: this.config.getOrThrow<string>('OLD_MYSQL_DATABASE'),
+      waitForConnections: true,
+      connectionLimit: 4,
+      namedPlaceholders: false,
+    };
+
+    this.pool = mysql.createPool(options);
+    return this.pool;
+  }
+}