Add Rz Coin utility store

scripts/ui/main.gd

@@ -207,6 +207,7 @@ func _build_ui() -> void:
 	header.add_child(account_chevron_button)
 
 	credits_badge = CreditsBadge.new()
+	credits_badge.store_requested.connect(func(): show_screen("rz_store"))
 	header.add_child(credits_badge)
 
 	var screens_container := MarginContainer.new()
@@ -355,6 +356,11 @@ func _build_ui() -> void:
 	donations.main = self
 	screens_container.add_child(donations)
 	screens["donations"] = donations
+	var rz_store := preload("res://scripts/ui/rz_store_screen.gd").new()
+	rz_store.name = "RzCoinStore"
+	rz_store.main = self
+	screens_container.add_child(rz_store)
+	screens["rz_store"] = rz_store
 
 	feedback_dialog = preload("res://scripts/ui/app_feedback_dialog.gd").new()
 	feedback_dialog.name = "AppFeedbackDialog"
@@ -426,6 +432,7 @@ func _populate_navigation(container: VBoxContainer, include_brand: bool) -> void
 	_add_nav_button(container, "flashcards", "Flashcards", "clipboard-plus", true, Brand.is_uat_environment())
 	_add_nav_button(container, "bookmarks", "Bookmarks", "bookmark", true)
 	_add_nav_button(container, "notes", "Notes", "notebook-pen", true)
+	_add_nav_button(container, "rz_store", "Rz Coin Store", "star", true)
 
 	var spacer := Control.new()
 	spacer.size_flags_vertical = Control.SIZE_EXPAND_FILL
@@ -476,6 +483,7 @@ func _on_navigation_pressed(key: String) -> void:
 		"notes": show_screen("notes")
 		"bookmarks": show_screen("bookmarks")
 		"donations": show_screen("donations")
+		"rz_store": show_screen("rz_store")
 		"logout": _logout()