docs: rewrite README.md

[jac3km4]

Rewrites README.md to enhance the structure, style, and instructions.

• Replaced old structure with clear headers (Introduction, Building, Using, Disclaimer, License).
• Included the required Ubuntu system dependencies for Bevy builds (pkg-config, libwayland-dev, etc.).
• Replaced the hardcoded path from the original author with a generic path (/home/user/...).
• Formatted with standard markdown elements (bolding, lists, code blocks, emojis).
• Verified the build passes with cargo build and cargo clippy -- -D warnings.

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PR created automatically by Jules for task 2005446408715133023 started by @jac3km4

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