Defer island saves until settings panel closes; apply click cooldown to all buttons

[Copilot]

Rapid clicking on settings menu buttons causes severe TPS drops (2-3 TPS with two players) because every flag change triggers an immediate database write via Island.setChanged() → IslandsManager.updateIsland(), and the existing click cooldown only applied to tab switches after click handlers already executed.

Deferred saves (Island.java, TabbedPanel.java)

• Added reference-counted beginDeferSaves()/endDeferSaves() on Island — while deferred, setChanged() marks dirty but skips the DB write
• TabbedPanel begins deferring on first open, ends on true close (single save)
• refreshing flag distinguishes panel rebuilds from actual inventory close events

// Island now batches saves
island.beginDeferSaves();
// ... many setFlag() / toggleFlag() calls — no DB writes ...
island.endDeferSaves(); // single save if changed

Click cooldown moved upstream (PanelListenerManager.java)

• onTimeout check moved from TabbedPanel.onInventoryClick() to PanelListenerManager.onInventoryClick() before click handlers and panel refresh execute
• Scoped to TabbedPanel listeners only — other panels unaffected
• Previously the cooldown ran after handlers, so flag changes and expensive panel rebuilds still happened on every rapid click

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
68.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud