Eda Install

Detect a machine's environment and install + verify the open-source EDA toolchain that the signoff-loop and def-graph skills need — OpenROAD-flow-scripts (openroad/yosys), iverilog, KLayout, Magic, Netgen, OpenSTA, the sky130A PDK, and the torch+torch_geometric graph venv. Use when setting up a new machine, when `check_env.sh` reports missing tools, when the user asks to install/bootstrap/provision the EDA tools or "set up the environment", or when a flow fails because a tool or PDK is absent. Without root it automatically installs a no-sudo path (pre-built conda litex-hub binaries + a venv on a big volume). Produces references/env.local.sh so a bootstrapped toolchain is …