Implement PostgreSQL and Redis adapters with Docker memory tests

[NeerajCodz]

This pull request introduces a new skill, rust-best-practices, which provides comprehensive guidelines and quick references for writing idiomatic, performant, and robust Rust code. The changes include the creation of a main skill file summarizing best practices, as well as detailed reference chapters covering linting, performance, and error handling.

The most important changes are:

Skill Introduction and Overview

• Added .agents/skills/rust-best-practices/SKILL.md, a skill definition file that summarizes idiomatic Rust practices, including borrowing vs cloning, error handling, performance, testing, generics, type state pattern, and documentation standards. It also links to detailed reference chapters for in-depth guidance.

Linting and Clippy Best Practices

• Added chapter_02.md detailing how to use Clippy for linting, important lints to respect, workflow integration, and workspace/package lint configuration. Emphasizes fixing warnings and using #[expect(...)] with justification instead of #[allow(...)].

Performance Optimization

• Added chapter_03.md focused on performance mindset, including benchmarking, profiling with flamegraph, avoiding redundant cloning, stack vs heap allocation strategies, and efficient use of iterators and zero-cost abstractions.

Error Handling Patterns

• Added chapter_04.md explaining robust error handling in Rust: preferring Result over panics, when to use unwrap/expect, leveraging thiserror for libraries and anyhow for binaries, error propagation with ?, and best practices for testing and async error types.