Centralized configuration management service setup

[Guddy1-tech]

closes #
#356

Summary

Adds a standalone NestJS configuration service for managing environment-specific settings, feature flags, encrypted secrets, and real-time configuration updates.

Changes

• Added Config, Environment, Secret, Version, Audit Log, and Webhook entities
• Added default dev, staging, and prod environments
• Added cached startup configuration endpoints
• Added API-key-protected configuration management endpoints
• Added AES-256-GCM secret encryption and key rotation
• Added immutable configuration version history and rollback
• Added configuration and secret audit logging
• Added signed webhook notifications with retry support
• Added Docker and PostgreSQL Compose configuration
• Added service setup and API documentation
• Added encryption and cache unit tests

Key Endpoints

• GET /v1/config/:service/:environment
• GET /v1/config/:service/:environment/resolve
• PUT /v1/config/:service/:environment/:key
• DELETE /v1/config/:service/:environment/:key
• PUT /v1/secrets/:service/:environment/:key
• POST /v1/secrets/:service/:environment/rotate
• GET /v1/versions/:resourceId
• POST /v1/versions/:resourceId/:version/rollback
• GET /v1/audit-logs
• GET|POST|PATCH /v1/webhooks

Security

• Administrative and secret endpoints require x-config-api-key
• Secret values are encrypted using AES-256-GCM
• Secret values are excluded from write, version, and audit responses
• Webhooks support HMAC-SHA256 signatures
• Audit entries identify callers through x-actor-id

Verification

• npm run build
• npm run type-check
• npm test
• 3 unit tests passing
• git diff --check
• Docker runtime test—not run because Docker is unavailable in the development workspace

Configuration

Required production variables:

• CONFIG_API_KEY
• ENCRYPTION_KEY
• DB_HOST
• DB_PORT
• DB_USER
• DB_PASSWORD
• DB_NAME

Generate an encryption key with:

openssl rand -base64 32

[drips-wave]

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Issue	Title
#356	Centralized Configuration Management Service Setup	Link to this issue
#361	Cache Warming and Preloading Service Setup	Link to this issue

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