docs: Add Apache 2.0 license file

[chadmf]

Summary

Add standard Apache License 2.0 file to the repository.

Changes

New File: LICENSE

• Added standard Apache License 2.0 (Version 2.0, January 2004)
• Full license text (176 lines)
• Standard terms and conditions for use, reproduction, and distribution

Why

• Provides clear licensing terms for the repository
• Standard open-source license
• Allows others to use, modify, and distribute the code
• Protects contributors with warranty disclaimers

License Details

Apache License 2.0 is a permissive license that:

• ✅ Allows commercial use
• ✅ Allows modification
• ✅ Allows distribution
• ✅ Allows private use
• ✅ Provides patent grant
• ✅ Requires license and copyright notice
• ✅ Requires state changes documentation

Does NOT:

• ❌ Provide warranty
• ❌ Hold contributors liable
• ❌ Grant trademark rights

Standards

• ✅ Uses official Apache License 2.0 text
• ✅ File named "LICENSE" (standard convention)
• ✅ Placed in repository root
• ✅ No modifications to standard license text

Checklist

• LICENSE file created with Apache 2.0 text
• File placed in repository root
• Standard license text used (unmodified)
• Commit message follows guidelines

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Ready to merge - Adds standard open-source license to repository.