feat: Phase 1 Modular Native Architecture (Feature Flags & features.h)

[ClausValcaTD]

Implemented Phase 1 Modular Native Architecture using C++ preprocessor guards, src/features.h, getCompiledFeatures() native addon export, JS layer features export, BrowserWindow openDevTools check, TypeScript definitions, and test_features.js.

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PR created automatically by Jules for task 9513703302766813322 started by @ClausValcaTD

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