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/components/game/prestigePanel.tsx

@@ -89,6 +89,7 @@ const PrestigePanel = (): JSX.Element => {
     buyPrestigeUpgrade,
     enableNotifications,
     enableSounds,
+    toggleAutoAdventurer,
     toggleAutoPrestige,
     triggerPrestigeToast,
   } = useGame();
@@ -110,7 +111,7 @@ const PrestigePanel = (): JSX.Element => {
     );
   }
 
-  const { prestige: prestigeData, player } = state;
+  const { autoAdventurer, prestige: prestigeData, player } = state;
   const threshold = calculateThreshold(prestigeData.count);
   const isEligible = player.totalGoldEarned >= threshold;
   const runestonePreview = calculateRunestonePreview(
@@ -173,6 +174,10 @@ const PrestigePanel = (): JSX.Element => {
     void handlePrestige();
   }
 
+  function handleAutoAdventurerToggle(): void {
+    toggleAutoAdventurer();
+  }
+
   function handleAutoPrestigeToggle(): void {
     toggleAutoPrestige();
   }
@@ -347,6 +352,9 @@ const PrestigePanel = (): JSX.Element => {
                       = prestigeData.runestones >= upgrade.runestonesCost;
                     const isLoading = buyingId === upgrade.id;
 
+                    const isAutoAdventurerToggle
+                      = upgrade.id === "auto_adventurer" && purchased;
+                    const autoAdventurerEnabled = autoAdventurer ?? false;
                     const isAutoPrestigeToggle
                       = upgrade.id === "auto_prestige" && purchased;
                     const autoPrestigeEnabled
@@ -381,6 +389,21 @@ const PrestigePanel = (): JSX.Element => {
                               : `🔮 ${formatNumber(upgrade.runestonesCost)} Runestones`}
                           </p>
                         </div>
+                        {isAutoAdventurerToggle
+                          ? <button
+                            className={`auto-prestige-toggle ${
+                              autoAdventurerEnabled
+                                ? "enabled"
+                                : "disabled"
+                            }`}
+                            onClick={handleAutoAdventurerToggle}
+                            type="button"
+                          >
+                            {autoAdventurerEnabled
+                              ? "⚡ Auto ON"
+                              : "⏸ Auto OFF"}
+                          </button>
+                          : null}
                         {isAutoPrestigeToggle
                           ? <button
                             className={`auto-prestige-toggle ${