Implement the 023-clear-encounter feature that adds a clear encounter button with confirmation dialog to remove all combatants and reset round/turn counters, with the cleared state persisting across page refreshes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/App.tsx

@@ -13,6 +13,7 @@ export function App() {
 		advanceTurn,
 		retreatTurn,
 		addCombatant,
+		clearEncounter,
 		removeCombatant,
 		editCombatant,
 		setInitiative,
@@ -94,6 +95,7 @@ export function App() {
 						encounter={encounter}
 						onAdvanceTurn={advanceTurn}
 						onRetreatTurn={retreatTurn}
+						onClearEncounter={clearEncounter}
 					/>
 				</div>