SB-010-BUILD_SYSTEM.md (P1, 416 lines)

• Build system for Dreamcast compilation and deployment
• Toolchain: sh-elf-gcc cross-compiler, KOS SDK, SPECTRE (optional)
• Installation: 3 options — Manual (apt + git clone KOS), Docker container, FROM House toolchain (source /from/toolchains/dreamcast/environ.sh)
• Project source structure: src/core/, src/utils/, include/, fonts/, tools/
• Build targets: all/debug/release/clean/distclean, elf/cdi P0: INVALID/iso, run/burn
• KOS-specific rules in kos.mk: defines -D_KOS -D_DREAMCAST -D__DC__, conditional SPECTRE integration
• CI pipeline: GitHub Actions with fromhouse/d3tui-toolchain:latest container
• Release artifacts: ELF, CDI P0: INVALID, ISO, source