#84: move 215 root files into a folder hierarchy

Everything lived in one flat directory, so a diff gave no clue what area it
touched and finding the file you wanted meant knowing its exact name. Twelve
folders now, grouped by what a thing IS rather than what type it is - a
vessel's definition, its component scenes and its upgrade resources sit
together, because that is the set you read when you change one of them.

  buildings  core  controllers  enemies  logistics  planets
  resources  shaders  surface  ui  vessels  vfx  world

332 files moved and every res:// reference rewritten - 306 files touched,
including the autoload and main-scene paths in project.godot. Nothing renamed:
this is purely where files sit, so the diff is a pile of pure moves and no
behaviour is buried in it. ui_theme.tres, icon.svg and web_shell.html stay at
the root, where Godot and the export preset expect them.

Verified three ways, because a suite alone would not have caught all of it:
the full 117 pass, the web export builds clean, and the game renders.

The export is why that matters. The FIRST export after the move failed with
"Attempt to open script 'res://GameState.gd'" - the old path - while
project.godot on disk plainly said res://core/GameState.gd. That is this
project's documented Android FUSE mtime trap: Godot served a cached copy of a
file whose content had changed. A `touch` fixed it. Nothing in the test suite
would have found that, because the suite runs from a copy on a native
filesystem - the one place the bug cannot happen.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

surface/CapturePoint.gd

@@ -0,0 +1,119 @@
+class_name CapturePoint
+extends Area2D
+
+# One point on a landed planet's surface that must be held (fleet ship
+# nearby, no enemy nearby) for capture_time seconds. Progress is polled by
+# distance each frame rather than through physics signals - same idiom as
+# RockField/GasVentField - since no collision response is needed, only
+# proximity.
+
+signal captured
+
+enum State { NEUTRAL, BLOCKED, CAPTURING, CAPTURED }
+
+@export var point_index: int = 0
+@export var capture_radius: float = 220.0
+@export var capture_time: float = 8.0
+@export var enemy_clear_radius: float = 700.0
+@export var drain_rate: float = 0.5
+
+const NEUTRAL_COLOR: Color = Color(0.55, 0.85, 1.0)
+const BLOCKED_COLOR: Color = Color(1.0, 0.3, 0.3)
+const CAPTURING_COLOR: Color = Color(0.4, 1.0, 0.55)
+const CAPTURED_COLOR: Color = Color(1.0, 0.85, 0.3)
+const CORE_RADIUS: float = 60.0
+
+var progress: float = 0.0
+var state: int = State.NEUTRAL
+
+
+func _ready() -> void:
+	# Behind the fleet and enemies, same convention as every other world
+	# object that must never occlude them (Planet.gd, Rock.gd, Building.gd,
+	# Hauler.gd, Transporter.gd, VesselDelivery.gd all set this in _ready()).
+	# "Is an enemy inside my capture radius" is the core read of this
+	# mechanic, so a ship or enemy sitting in the ring must stay fully visible.
+	z_index = -1
+	queue_redraw()
+
+
+# Called by PlanetSetupHost when this point was already captured on a
+# previous visit, so re-landing restores it instead of starting the fill
+# over. Permanent for the run - _process() below returns early once
+# CAPTURED and never re-evaluates it.
+func mark_captured() -> void:
+	progress = 1.0
+	state = State.CAPTURED
+	queue_redraw()
+
+
+func _process(delta: float) -> void:
+	if state == State.CAPTURED:
+		return
+
+	var enemy_nearby: bool = _enemy_nearby()
+	var ship_in_range: bool = _ship_in_range()
+
+	if enemy_nearby:
+		state = State.BLOCKED
+		progress = maxf(progress - drain_rate * delta / capture_time, 0.0)
+	elif ship_in_range:
+		state = State.CAPTURING
+		progress = minf(progress + delta / capture_time, 1.0)
+		if progress >= 1.0:
+			state = State.CAPTURED
+			GameState.mark_point_captured(GameState.planet_id, point_index)
+			captured.emit()
+	else:
+		state = State.NEUTRAL
+		progress = maxf(progress - drain_rate * delta / capture_time, 0.0)
+	queue_redraw()
+
+
+func _ship_in_range() -> bool:
+	for ship in get_tree().get_nodes_in_group("player_ships"):
+		if is_instance_valid(ship) and global_position.distance_to(ship.global_position) <= capture_radius:
+			return true
+	return false
+
+
+func _enemy_nearby() -> bool:
+	for enemy in get_tree().get_nodes_in_group("enemies"):
+		if is_instance_valid(enemy) and global_position.distance_to(enemy.global_position) <= enemy_clear_radius:
+			return true
+	return false
+
+
+func _state_color() -> Color:
+	match state:
+		State.BLOCKED:
+			return BLOCKED_COLOR
+		State.CAPTURING:
+			return CAPTURING_COLOR
+		State.CAPTURED:
+			return CAPTURED_COLOR
+		_:
+			return NEUTRAL_COLOR
+
+
+func _draw() -> void:
+	var color: Color = _state_color()
+	# Outer ring: the actual capture radius, faint - tells the player how
+	# close they need to stay without dominating the screen.
+	_draw_ring(capture_radius, 0.0, TAU, color, 0.35)
+	# Inner beacon: fixed size regardless of capture_radius, so it reads
+	# clearly even when zoomed out. A filling arc sweeps clockwise from the
+	# top as progress advances, same "fill toward completion" idea as
+	# VesselGasBomberComponent's hull fill, adapted to a ring since a
+	# capture point has no hull.
+	_draw_ring(CORE_RADIUS, 0.0, TAU, color, 1.0)
+	if progress > 0.001:
+		var sweep: float = TAU * progress
+		_draw_ring(CORE_RADIUS, -PI / 2.0, -PI / 2.0 + sweep, color, 1.0, 10.0)
+
+
+func _draw_ring(radius: float, from_angle: float, to_angle: float, color: Color, alpha: float,
+		core_width: float = 6.0) -> void:
+	draw_arc(Vector2.ZERO, radius, from_angle, to_angle, 64, Color(color, 0.16 * alpha), core_width * 2.6, true)
+	draw_arc(Vector2.ZERO, radius, from_angle, to_angle, 64, Color(color, 0.5 * alpha), core_width, true)
+	draw_arc(Vector2.ZERO, radius, from_angle, to_angle, 64, Color(1.0, 0.96, 0.9, 0.9 * alpha), core_width * 0.3, true)