ESFEX v0.1.5

Fixed

• Grid Builder demand forecast not persisted (#7) — applying the step-3
  demand forecast only stored per-node summary stats and never wrote the hourly
  series to disk nor recorded a CSV path, so the saved config carried empty
  demand_paths and the runner had no per-node demand. The forecast is now
  written to per-node CSV files (under a demand/ folder next to the project)
  and wired into each node, so demand_paths is emitted and the runner finds
  the files.

Full changelog: v0.1.4...v0.1.5