chore: add techbase to apps-archived

Integrated techbase (software comparison platform) into monorepo structure:
- Created NestJS backend with votes and comments modules
- Migrated from external Supabase to own PostgreSQL
- Set up Drizzle ORM schema for votes and comments
- Created API client replacing Supabase in Astro frontend
- Added environment configuration (port 3021)

Archived immediately as it's not yet ready for active development.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps-archived/techbase/apps/backend/src/db/database.module.ts

@@ -0,0 +1,28 @@
+import { Module, Global, OnModuleDestroy } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { getDb, closeConnection, type Database } from './connection';
+
+export const DATABASE_CONNECTION = 'DATABASE_CONNECTION';
+
+@Global()
+@Module({
+	providers: [
+		{
+			provide: DATABASE_CONNECTION,
+			useFactory: (configService: ConfigService): Database => {
+				const databaseUrl = configService.get<string>('DATABASE_URL');
+				if (!databaseUrl) {
+					throw new Error('DATABASE_URL environment variable is not set');
+				}
+				return getDb(databaseUrl);
+			},
+			inject: [ConfigService],
+		},
+	],
+	exports: [DATABASE_CONNECTION],
+})
+export class DatabaseModule implements OnModuleDestroy {
+	async onModuleDestroy() {
+		await closeConnection();
+	}
+}