Feat: Implements Redis database backend

[Oxazolidinone]

PR Description: Add Redis Vector Storage Backend

Summary

This PR adds a Redis backend for the vector storage system, enabling scalable, high-performance similarity search using Redis Stack with RediSearch. It supports multiple distance metrics, robust error handling, and workspace-specific configuration.

Usage

Using Docker (local host)

docker run -d --name redis-vector-db -p 6379:6379 redis/redis-stack-server:latest

Enviroment configuration

VECTOR_STORE_TYPE=redis
VECTOR_STORE_DISTANCE=cosine
VECTOR_STORE_COLLECTION=vector-storage-memory
REDIS_DATABASE=0

# Option 1: Use URL (works for both local & cloud)
#   - redis://  → no SSL (local)
#   - rediss:// → SSL/TLS (Redis Cloud)
VECTOR_STORE_URL=rediss://default:<password>@<host>:<port>

# Option 2: Use host/port (works for both local & cloud)
VECTOR_STORE_HOST=<host>
VECTOR_STORE_PORT=<port>
VECTOR_STORE_PASSWORD=<password>
VECTOR_STORE_USERNAME=<username>

Features

• Core Backend Implementation
  • RedisBackend class implementing the VectorStore interface
  • Supports distance metrics: COSINE, L2 (Euclidean), IP (Inner Product)
  • RediSearch-powered vector indexing and querying
  • Workspace and global configuration support
  • Automatic distance metric normalization for enum validation
• Data Persistence
  • Vectors and metadata stored in Redis JSON documents
  • Collection management via RediSearch indices
  • Atomic operations for insert, update, delete
• Search Capabilities
  • KNN similarity search with configurable result limits
  • Distance-based scoring per metric
  • Metadata filters (range operators: gte, lte, gt, lt, any)
  • Pagination and sorting support
• Configuration Integration
  • Environment variable support for all Redis connection options
  • Zod schema validation for config
  • Factory integration for backend selection and workspace fallback
  • Default configuration with sensible defaults

Testing

• Unit tests for connect, insert, search, update, delete, and list operations
• Metric-specific tests for COSINE, L2, and IP scoring
• Error handling tests for invalid operations and connection issues
• Filter support tests: range queries, any filters
• Mock implementations for Redis client and RediSearch interactions

[willingWill17]

The Redis instance contains 16 separate databases, numbered from 0 to 15. However, database 0 failed to initialize. Please also verify the database separation, as the mentioned database remained empty even after data was saved.