Add prerequisites for project setup

[jnakaigen]

Description

This PR improves the Development Setup documentation by adding a clear Prerequisites section.

Changes made:

1. Added Prerequisites List: Explicitly listed the required tools (Go, Node.js) and optional tools (Docker, Tmux) needed to run the project. This helps new contributors avoid "command not found" errors during initial setup.
2. Added Windows Warning: Added a note clarification that the setup.sh script (which uses tmux) is intended for Linux/macOS, and directed Windows users to follow the Manual Setup instructions instead.

• Fixes: N/A (Documentation improvement)

Checklist

• Ran npx prettier --write . (for formatting)
• Ran gofmt -w . (for Go backend)
• Ran npm test (for JS/TS testing)
• Added unit tests, if applicable
• Verified all tests pass
• Updated documentation, if needed

Additional Notes

These changes were motivated by my own experience setting up the project on Windows. Clarifying the prerequisites upfront will streamline the onboarding process for future Windows contributors.

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