Add real farm worker harvesting

coalgov-wiki-pages/npcs.txt

@@ -18,7 +18,8 @@ Create workers and a trader in that zone:
 
 The default supply chain is:
 
-  * Farmer produces WHEAT.
+  * Farmer scans the farm zone for mature WHEAT, CARROTS, POTATOES, and BEETROOTS.
+  * Farmer walks to mature crops, harvests drops into NPC inventory, and replants if it has the seed or crop item.
   * Baker pulls WHEAT from same-zone NPC inventories.
   * Baker consumes 3 WHEAT to produce 2 BREAD.
   * Workers keep a reserve and move surplus output to same-zone traders.
@@ -38,13 +39,24 @@ Worker roles are matched by NPC name under ''npc.worker.roles''. For example, an
       tick_interval_seconds: 20
       roles:
         farmer:
+          behavior: FARM
           output_material: WHEAT
           output_amount: 4
+          crops:
+            - WHEAT
+            - CARROTS
+            - POTATOES
+            - BEETROOTS
+          replant: true
         baker:
+          behavior: CRAFT
           output_material: BREAD
           output_amount: 2
           inputs:
             WHEAT: 3
+      farm:
+        action_distance: 3.0
+        max_scan_blocks: 512
     supply_chain:
       max_transfer_per_tick: 64
       source_reserve: 16