Herblore: herbs, potions with charges, one per skill

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -37,6 +37,11 @@ Alpha. One season, bandit raids plus two friendly events, six buildings.
   fight while their points last, and praying trains Prayer too. A Temple adds
   points per bone and lets players offer bones as devotion, which wards the
   city in the next raid.
+- **Herblore:** farmers grow six herbs (guam to snapdragon); herblore brews
+  them with a secondary into potions of 50 uses. One potion per skill at a
+  time: faster gathering, a chance to keep materials or double ore, more
+  prayer from bones, or combat power, armour and healing. An empty potion is
+  replaced from the bank automatically.
 - **Events:** raids are announced a day or two ahead. Intel (spymaster's
   guild + scout reconnaissance) narrows down when, how strong, and finally
   where their camp is, so fighters can sabotage it. Defeat kills or drives