feat: recover M3-M4 untracked files, add .gitignore
- Add ARM64 support files never committed to monorepo:
entry_aarch64.zig, gic.zig, virtio_mmio.zig, littlefs_hal.zig,
linker_aarch64.ld, linker_user_aarch64.ld, run_aarch64.sh
- Add build scripts: build_full.sh, build_nim.sh, build_lwip.sh
- Add Libertaria LWF adapters: lwf_adapter.zig, lwf_membrane.zig
- Add LittleFS bridge: lfs_bridge.nim, lfs_rumpk.h
- Add freestanding headers: math.h, stdio.h, stdlib.h
- Add .gitignore blocking build artifacts and internal dirs
Markus Maiwald
72caf911b1