feat(mcp): add database tools for direct Redis connections

[joshrotenberg]

Summary

Add 23 new MCP tools for direct Redis database interaction, enabling AI agents to query, inspect, and diagnose Redis databases through natural conversation.

Closes #564

New Tools (23 total)

Server Info (6)

• database_ping - Ping the Redis server
• database_info - Get server information (INFO)
• database_dbsize - Get number of keys in database
• database_module_list - List loaded modules
• database_client_list - Get connected clients
• database_config_get - Get configuration values

Key Operations (7)

• database_scan - Scan keys matching a pattern (safe alternative to KEYS)
• database_type - Get key type
• database_ttl - Get key TTL in seconds
• database_exists - Check if key exists
• database_memory_usage - Get memory usage of a key
• database_get - Get string key value
• database_execute - Execute arbitrary Redis command

Data Structures (10)

• database_hgetall - Get all hash fields
• database_hlen - Get hash length
• database_lrange - Get list range
• database_llen - Get list length
• database_smembers - Get set members
• database_scard - Get set cardinality
• database_zrange - Get sorted set range
• database_zcard - Get sorted set cardinality
• database_slowlog - Get slow log entries
• database_slowlog_len - Get slow log length

Features

• Database Profile Integration: Uses the new Database profile type for connection credentials (host, port, password, TLS, username, database number)
• Read-Only Mode Protection: Write commands (SET, DEL, FLUSHDB, etc.) are blocked by default; use --allow-writes to enable
• Generic Execute Tool: database_execute allows arbitrary Redis commands for flexibility
• Lazy Connection: Connection is established on first tool use, not server startup
• Full TLS Support: Uses tokio-rustls for secure connections to Redis Cloud and other TLS-enabled instances

Implementation

• New database_tools.rs module with DatabaseTools struct and ConnectionManager
• Parameter structs and 23 tool implementations in server.rs
• Updated mcp tools command output (now shows 78 total tools)
• Integration test for local Redis validation

Testing

# Unit tests
cargo test -p redisctl-mcp

# Integration test (requires local Redis + local-redis profile)
cargo test -p redisctl-mcp -- --ignored test_database_tools_integration

# View tools list
cargo run -- mcp tools

Tool Count

Category	Count
Cloud	7
Enterprise	48
Database	23
Total	78