feat: rework modules, items and fuel

docs/ITEMS.md

@@ -33,10 +33,9 @@ The intended categories are:
 2. processed industrial goods
 3. life-support goods
 4. civilian goods
-5. fuel and power-chain goods
-6. construction goods
-7. population-related units
-8. special logistics goods later
+5. construction goods
+6. population-related units
+7. special logistics goods later
 
 ## Raw Resources
 
@@ -86,20 +85,6 @@ Current important example:
 
 These goods should matter for workforce health, quality of life, and possibly future growth modifiers.
 
-## Fuel And Power-Chain Goods
-
-These are the goods that keep ships and stations running.
-
-Examples:
-
-- gas as an energy-chain input
-- fuel as a refined operational good
-
-The exact chain may evolve, but the important distinction is:
-
-- some goods are energy inputs
-- some goods are operational fuels
-
 ## Construction Goods
 
 These are the goods used to build stations and possibly ships.
@@ -116,7 +101,7 @@ Construction storage at a station site should create demand for these goods thro
 
 ## Population-Related Units
 
-Population itself should be treated as a tracked resource, but not as an ordinary trade good in the same sense as metal or fuel.
+Population itself should be treated as a tracked resource, but not as an ordinary trade good in the same sense as ore.
 
 Important distinctions:
 
@@ -144,12 +129,6 @@ The current design implies at least these roles:
 - `ore`
   - raw industrial input
 
-- `gas`
-  - raw fuel-chain input
-
-- `fuel`
-  - operational energy good
-
 - `food`
   - workforce life-support
 
@@ -173,12 +152,11 @@ Not every item should necessarily fit in every hold type forever.
 
 Useful distinctions later may include:
 
-- bulk industrial cargo
-- liquid cargo
-- gas cargo
-- containerized finished goods
-- human transport capacity
-- livestock capacity
+- solid storage 
+- liquid storage
+- container storage
+- passengers
+- livestock
 
 For now, the important rule is simply:
 
@@ -191,7 +169,6 @@ Items should participate in the market according to their role.
 Examples:
 
 - life-support goods generate recurring demand
-- fuel goods generate operational demand
 - construction goods generate burst demand during expansion
 - industrial goods feed production chains
 - worker transport supports station staffing
@@ -220,7 +197,7 @@ The following rules should remain true unless deliberately revised:
 
 - workforce depends on real support goods
 - station construction depends on real construction goods
-- fuel and industrial chains are item-based
+- industrial chains are item-based
 - workers are movable population units
 - commanders are not ordinary trade cargo
 - livestock is distinct from workers