feat(ui): zoom-based LoD for star map labels

Labels now appear based on zoom level and system importance:
- Always: selected + hovered
- Zoom >= 1.2: hubs, junctions, gateway
- Zoom >= 2.0: all named systems
- Below 1.2: only selected/hovered

Prevents label soup at overview zoom levels.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/ui/star_map.gd

@@ -415,25 +415,35 @@ func _draw_systems(center: Vector2) -> void:
 
 		draw_circle(pos, radius, color)
 
-		# System name label — centered below the dot
+		# System name label — centered below dot, zoom-based LoD
 		var label: String = node.get("proper_name", "")
 		if not label.is_empty() and label != sid:
-			var label_color: Color
+			var show_label := false
 			if sid == _selected_system or sid == _hovered_system:
-				label_color = COLOR_TEXT
-			else:
-				label_color = COLOR_TEXT_DIM
-			var font := get_theme_default_font()
-			var label_size := font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9)
-			draw_string(
-				font,
-				pos + Vector2(-label_size.x / 2.0, radius + 10.0),
-				label,
-				HORIZONTAL_ALIGNMENT_LEFT,
-				-1,
-				9,
-				label_color,
-			)
+				show_label = true  # always show selected/hovered
+			elif _zoom >= 2.0:
+				show_label = true  # zoomed in: show all
+			elif _zoom >= 1.2:
+				show_label = topology in ["hub", "junction", ""]  # medium: hubs + junctions + gateway
+			# else: zoomed out, only selected/hovered
+
+			if show_label:
+				var label_color: Color
+				if sid == _selected_system or sid == _hovered_system:
+					label_color = COLOR_TEXT
+				else:
+					label_color = COLOR_TEXT_DIM
+				var font := get_theme_default_font()
+				var label_size := font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9)
+				draw_string(
+					font,
+					pos + Vector2(-label_size.x / 2.0, radius + 10.0),
+					label,
+					HORIZONTAL_ALIGNMENT_LEFT,
+					-1,
+					9,
+					label_color,
+				)
 
 
 func _draw_edges(center: Vector2) -> void: