✨ feat(auth): add API key management for STT/TTS services

- Add api_keys schema in mana-core-auth with SHA-256 hashing
- Create NestJS module with CRUD endpoints and validation
- Add external auth module to STT/TTS for sk_live_ key validation
- Create web UI page at /api-keys for key management
- Support rate limiting per key with configurable limits
- Cache validation results for 5 minutes to reduce auth service load

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

services/mana-core-auth/src/api-keys/api-keys.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { ApiKeysController } from './api-keys.controller';
+import { ApiKeysService } from './api-keys.service';
+
+@Module({
+	controllers: [ApiKeysController],
+	providers: [ApiKeysService],
+	exports: [ApiKeysService],
+})
+export class ApiKeysModule {}