refactor(ui): star map registers as implant/map/starchart

Deeper taxonomy: map is a family of views (starchart, system, station,
planet, location), not one app. Same HudGroups mechanics — just a
more specific path.

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

client/ui/star_map.gd

@@ -119,7 +119,7 @@ func _ready() -> void:
 	add_child(_info_panel)
 
 	# D-170: Register with HUD visibility groups
-	HudGroups.register(self, "implant/map")
+	HudGroups.register(self, "implant/map/starchart")
 
 	_load_data()
 	if _data_loaded:
@@ -146,7 +146,7 @@ func set_insert_active(active: bool) -> void:
 ## Toggle visibility via HUD group system (D-170).
 ## Opens implant/map (hides gameplay) or closes it (returns to gameplay).
 func toggle_visible() -> void:
-	HudGroups.toggle_app("implant/map")
+	HudGroups.toggle_app("implant/map/starchart")
 	if visible:
 		_dirty = true