Add component datasheets for re-bba-rb board (via LFS)

Store datasheets for the parts actually placed in the current design,
grouped under hardware/re-bba-rb/datasheets/ by sheet (fpga, power,
usb, ethernet). Filenames normalised to the part MPN. All tracked
through git-lfs per .gitattributes (*.pdf).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.devcontainer/Dockerfile

@@ -3,6 +3,7 @@ FROM debian:sid-slim
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates \
     git \
+    git-lfs \
     python3 \
     python3-venv \
     python3-pip \