Epic: Logistics & throughput

[ApocDev]

Surface the physical logistics a plan implies: how many belts, inserters, and rocket launches are needed to move each good, using the player's current research. This is mostly display on top of the existing solve, plus the prototype-data import each piece needs (belt and inserter prototypes, item weight).

Sub-issues:

• Logistics throughput: belts & inserters in/out per row #21 — belts and inserters needed per block row.
• Rocket-launch logistics: launches/min per item #22 — rocket-launch logistics (launches per minute per item).