refactor(ui): add implant container frame to minimap (#787)

Draw ImplantTheme-styled StyleBoxFlat behind the circular minimap for
visual consistency with other implant components. Stance badge icons
remain blocked by #795 (visual team).

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

client/ui/minimap.gd

@@ -35,11 +35,25 @@ const COLOR_CARDINAL: Color = Color(0.784, 0.816, 0.878, 0.4)  # Dimmer E/S/W ti
 const COLOR_PLAYER: Color = Constants.ENTITY_COLOR_PLAYER
 
 var _insert_active: bool = true
+# D-169: StyleBoxFlat matching ImplantPanel aesthetic — drawn as container frame behind the circle.
+var _container_style: StyleBoxFlat = null
 
 
 func _ready() -> void:
 	mouse_filter = Control.MOUSE_FILTER_IGNORE
 	set_process(true)
+	_init_container_style()
+
+
+func _init_container_style() -> void:
+	var t := load("res://ui/implant/default_implant.tres") as ImplantTheme
+	if not t:
+		return
+	_container_style = StyleBoxFlat.new()
+	_container_style.bg_color = t.panel_bg
+	_container_style.border_color = t.separator
+	_container_style.set_border_width_all(int(t.border_width))
+	_container_style.set_content_margin_all(0)
 
 
 func _process(_delta: float) -> void:
@@ -55,6 +69,11 @@ func set_insert_active(active: bool) -> void:
 
 
 func _draw() -> void:
+	# D-169: ImplantPanel-style container frame behind the circular minimap.
+	# Gives the minimap the same panel border aesthetic as other implant components.
+	if _container_style:
+		_container_style.draw(get_canvas_item(), Rect2(Vector2.ZERO, get_rect().size))
+
 	var sz: Vector2 = get_rect().size
 	var center := sz / 2.0
 	# Outer radius: fill control with 1px edge padding