Update to version 1.0.0 with breaking env var change

[jkebinger]

Summary

• Breaking Change: Environment variable renamed from REFORGE_SDK_KEY to REFORGE_BACKEND_SDK_KEY
• Version bumped to 1.0.0
• Cleaned up README (removed "under development" notice)

Breaking Change Details

The SDK now looks for the environment variable REFORGE_BACKEND_SDK_KEY instead of REFORGE_SDK_KEY when initializing without an explicit SDK key.

Users will need to update their environment configuration:

# Old (no longer works)
export REFORGE_SDK_KEY=your-key

# New (required)
export REFORGE_BACKEND_SDK_KEY=your-key

See sdk_reforge/options.py:83 for implementation.

Test plan

• Verify SDK initialization with REFORGE_BACKEND_SDK_KEY environment variable
• Verify SDK initialization with explicit sdk_key parameter still works
• Verify fallback to PREFAB_API_KEY still works

🤖 Generated with Claude Code

[jdwyah]

thanks