chore: add nix setup

[shini4i]

No description provided.

[Copilot]

Pull Request Overview

This PR adds Nix development environment support to the project by introducing a flake configuration for packaging and development.

• Adds a Nix flake configuration that packages the bash script as a derivation
• Creates a development shell with required dependencies (kubectl, yq-go, bats)
• Enables direnv integration for automatic environment activation

Reviewed Changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated 2 comments.

File	Description
flake.nix	Defines Nix package derivation and development shell with project dependencies
.envrc	Enables direnv to automatically load the Nix flake environment

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[Copilot]

Pull Request Overview

Copilot reviewed 7 out of 9 changed files in this pull request and generated no new comments.

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