fix(fly): persist fly mode and restore on join (#6403)

Persist /fly state in userdata and re-enable allowFlight on login so
flight isn’t lost after relogging on ground (upstream #6344).

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### Information

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This PR fixes #6344 

### Details

**Proposed fix:**    
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Persist the /fly state to userdata and restore allowFlight on login so
flight isn’t lost after relogging while on the ground.

**Environments tested:**    

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OS: Ubuntu 24.04

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Java version: 21

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- [x] Most recent Paper version (1.XX.Y, git-Paper-BUILD)
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- [ ] CraftBukkit/Spigot/Paper 1.12.2
- [ ] CraftBukkit 1.8.8

---------

Co-authored-by: JRoy <10731363+JRoy@users.noreply.github.com>

Author: Touchie771

Essentials/src/main/java/com/earth2me/essentials/EssentialsPlayerListener.java

@@ -503,12 +503,20 @@ private void joinFlow(final User user, final long currentTime, final String mess
             });
         }
 
+        final boolean restoreFly = user.isFlyModeEnabled() && user.isAuthorized("essentials.fly");
+        if (restoreFly) {
+            user.getBase().setAllowFlight(true);
+            if (ess.getSettings().isSendFlyEnableOnJoin()) {
+                user.sendTl("flyMode", CommonPlaceholders.enableDisable(user.getSource(), true), user.getDisplayName());
+            }
+        }
+
         if (user.isAuthorized("essentials.fly.safelogin")) {
             user.getBase().setFallDistance(0);
             if (LocationUtil.shouldFly(ess, user.getLocation())) {
                 user.getBase().setAllowFlight(true);
                 user.getBase().setFlying(true);
-                if (ess.getSettings().isSendFlyEnableOnJoin()) {
+                if (!restoreFly && ess.getSettings().isSendFlyEnableOnJoin()) {
                     user.sendTl("flyMode", CommonPlaceholders.enableDisable(user.getSource(), true), user.getDisplayName());
                 }
             }
@@ -524,6 +532,11 @@ private void joinFlow(final User user, final long currentTime, final String mess
             ess.getLogger().log(Level.INFO, "Set socialspy to false for {0} because they had it enabled without permission.", user.getName());
         }
 
+        if (user.isFlyModeEnabled() && !user.isAuthorized("essentials.fly")) {
+            user.setFlyModeEnabled(false);
+            ess.getLogger().log(Level.INFO, "Set fly mode to false for {0} because they had it enabled without permission.", user.getName());
+        }
+
         if (user.isGodModeEnabled() && !user.isAuthorized("essentials.god")) {
             user.setGodModeEnabled(false);
             ess.getLogger().log(Level.INFO, "Set god mode to false for {0} because they had it enabled without permission.", user.getName());

Essentials/src/main/java/com/earth2me/essentials/UserData.java

@@ -469,6 +469,15 @@ public void setGodModeEnabled(final boolean set) {
         config.save();
     }
 
+    public boolean isFlyModeEnabled() {
+        return holder.flyMode();
+    }
+
+    public void setFlyModeEnabled(final boolean set) {
+        holder.flyMode(set);
+        config.save();
+    }
+
     public boolean getMuted() {
         return holder.muted();
     }

Essentials/src/main/java/com/earth2me/essentials/commands/Commandfly.java

@@ -34,6 +34,8 @@ protected void togglePlayer(final CommandSource sender, final User user, Boolean
             user.getBase().setFallDistance(0f);
             user.getBase().setAllowFlight(enabled);
 
+            user.setFlyModeEnabled(enabled);
+
             if (!user.getBase().getAllowFlight()) {
                 user.getBase().setFlying(false);
             }

Essentials/src/main/java/com/earth2me/essentials/config/holders/UserConfigHolder.java

@@ -171,6 +171,16 @@ public void godMode(final boolean value) {
         this.godmode = value;
     }
 
+    private boolean flymode = false;
+
+    public boolean flyMode() {
+        return this.flymode;
+    }
+
+    public void flyMode(final boolean value) {
+        this.flymode = value;
+    }
+
     private boolean muted = false;
 
     public boolean muted() {