What ratio and time for cold brew that does not taste harsh

1:8 coffee to water by weight for a concentrate, 16 to 18 hours in the fridge, coarse grind. Harshness at that ratio is usually grind size rather than time: too fine and you over-extract even cold.

Plan four, not seven, and make one of them deliberately trivial. The plans that fail are the ones with no slack, because a single late evening cascades into ordering food for the rest of the week.

The reporting layer, until something forces it. It is the part that feels productive to build and the part nobody opens twice.