feat: rework modules, items and fuel

docs/ECONOMY.md

@@ -84,7 +84,6 @@ A buy order should include, conceptually:
 Buy orders let a station express:
 
 - production input demand
-- fuel shortages
 - construction material shortages
 - military resupply needs
 
@@ -138,8 +137,6 @@ The station commander should:
 
 Without a station commander, a station should not act like a healthy market participant.
 
-If the station has no fuel and therefore no power, it should not continue normal market operation.
-
 However, there is an important exception during founding or emergency intervention:
 
 - a higher actor may force transfers toward the station or construction site even without ordinary market behavior
@@ -149,7 +146,7 @@ Recommended review loop:
 1. inspect current inventory
 2. inspect production queues or goals
 3. inspect incoming and outgoing reservations
-4. inspect fuel, defense, and construction reserves
+4. inspect defense, and construction reserves
 5. update buy orders
 6. update sell orders
 7. request logistics or strategic help if necessary
@@ -185,7 +182,7 @@ The intended economy should eventually support flows such as:
 1. extract raw resources
 2. move them to useful stations
 3. refine or process them
-4. consume them for fuel, production, or expansion
+4. consume them for production or expansion
 5. produce intermediate and advanced goods
 6. sell surpluses or acquire shortages through the market
 
@@ -200,7 +197,6 @@ Logistics should emerge from market demand, not only from hardcoded behavior loo
 Examples:
 
 - a hauler sees a profitable sell-to-buy opportunity
-- a station commander requests urgent fuel delivery
 - a faction commander subsidizes strategic resource movement
 
 This is a better long-term basis than one-off scripted “mine and deliver to this exact station” logic.
@@ -208,7 +204,6 @@ This is a better long-term basis than one-off scripted “mine and deliver to th
 Traders should generally prefer the best reachable buy opportunity within their allowed operational range, subject to:
 
 - travel time
-- fuel cost
 - risk
 - behavioral restrictions
 - territorial or regional limits
@@ -236,7 +231,6 @@ The economy will work better if stations can reserve expected inventory changes.
 
 Examples:
 
-- incoming fuel is reserved for station power
 - outbound metals are reserved for a construction project
 - a hauler claims part of a sell order before pickup