feat: post-prestige automation (auto-adventurer) (#76)

## Summary

Closes #61

- Adds the **Autonomous Recruitment** prestige upgrade (50 runestones) to both the API and web data files
- Adds `autoAdventurer?: boolean` to the `GameState` type for backwards-compatible saves
- Adds tick-loop logic in GameContext that automatically purchases the highest-tier unlocked adventurer the player can afford each frame when the toggle is enabled
- Adds `toggleAutoAdventurer` callback and exposes it through the context
- Adds toggle UI in the Prestige Shop (mirrors the existing Auto-Prestige toggle pattern)
- Updates the How to Play guide in the About panel to document the new automation feature

✨ This issue was created with help from Hikari~ 🌸

Reviewed-on: #76
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

apps/web/src/context/gameContext.tsx

@@ -447,6 +447,11 @@ interface GameContextValue {
    */
   toggleAutoBoss: ()=> void;
 
+  /**
+   * Toggle the auto-adventurer setting on/off (requires auto_adventurer prestige upgrade).
+   */
+  toggleAutoAdventurer: ()=> void;
+
   /**
    * Queue of newly unlocked codex entry IDs (for toast notifications).
    */
@@ -1073,6 +1078,42 @@ export const GameProvider = ({
           }
         }
 
+        // Auto-adventurer: buy one of the highest-tier affordable unlocked adventurer per tick
+        if (
+          next.autoAdventurer === true
+          && next.prestige.purchasedUpgradeIds.includes("auto_adventurer")
+        ) {
+          const [ bestAdventurer ] = next.adventurers.
+            filter((adventurer) => {
+              const cost
+                = adventurer.baseCost * Math.pow(1.15, adventurer.count);
+              return adventurer.unlocked && next.resources.gold >= cost;
+            }).
+            sort((adventurerA, adventurerB) => {
+              const costA
+                = adventurerA.baseCost * Math.pow(1.15, adventurerA.count);
+              const costB
+                = adventurerB.baseCost * Math.pow(1.15, adventurerB.count);
+              return costB - costA;
+            });
+          if (bestAdventurer !== undefined) {
+            const purchaseCost
+              = bestAdventurer.baseCost * Math.pow(1.15, bestAdventurer.count);
+            next = {
+              ...next,
+              adventurers: next.adventurers.map((adventurer) => {
+                return adventurer.id === bestAdventurer.id
+                  ? { ...adventurer, count: adventurer.count + 1 }
+                  : adventurer;
+              }),
+              resources: {
+                ...next.resources,
+                gold: next.resources.gold - purchaseCost,
+              },
+            };
+          }
+        }
+
         // Detect newly unlocked achievements
         unlockedAchievementsReference.current = next.achievements.filter(
           (a, index) => {
@@ -1858,6 +1899,18 @@ export const GameProvider = ({
     });
   }, []);
 
+  const toggleAutoAdventurer = useCallback(() => {
+    setState((previous) => {
+      if (previous === null) {
+        return previous;
+      }
+      return {
+        ...previous,
+        autoAdventurer: previous.autoAdventurer !== true,
+      };
+    });
+  }, []);
+
   const setActiveCompanion = useCallback((companionId: string | null) => {
     setState((previous) => {
       if (previous === null) {
@@ -2169,6 +2222,7 @@ export const GameProvider = ({
       startQuest,
       state,
       syncError,
+      toggleAutoAdventurer,
       toggleAutoBoss,
       toggleAutoPrestige,
       toggleAutoQuest,
@@ -2240,6 +2294,7 @@ export const GameProvider = ({
     startQuest,
     state,
     syncError,
+    toggleAutoAdventurer,
     toggleAutoBoss,
     toggleAutoPrestige,
     toggleAutoQuest,