Phase 16: Save/load full coverage + autosave + UI

Three-agent fan-out reusing the contracts-first pattern: Opus pre-wrote
World.clear_all + 4 EventBus signals (save_started/finished, load_started/
finished) before dispatch. Pattern proven across Phases 12/13/14/15/16.

Entity to_dict/from_dict + class_id tagging (Agent A):
- class_id tag added to all 18 entity to_dict methods for loader routing
- Missing pairs filled in: wolf, grave_slot, graveyard_zone, stockpile_zone,
  crate (from_dict). All defensive with d.get(field, default).
- Workbench round-trips label_text so Carpenter/Smelter/Millstone/Hearth/
  Pyre kinds survive reload
- BeautySystem + DirtinessSystem save_dict/apply_dict for sparse maps
- World.save_tilemap_layers / apply_tilemap_layers covering 5 layers
  (Terrain/Floor/Wall/Designation/Roof; Fog runtime-only skipped)

SaveSystem v2 rewrite (Agent B):
- SAVE_VERSION bumped from 1 to 2
- write_save(slot) pauses Sim, emits save_started, collects every entity
  via _collect_entities iterating all World registries, writes payload to
  user://save_<slot>.json
- apply_save full rewrite: pause sim → emit load_started → World.clear_all
  → apply autoloads (GameState/Clock/Weather/Storyteller) → apply tilemap
  layers → iterate payload.entities and dispatch to per-class factories
  → apply beauty/dirt maps → emit load_finished(slot, ok, real_seconds_away)
- Per-class factory registry: 18 class_ids dispatched to setup+add_child+
  from_dict patterns. CremationPyre detected via workbench.label_text == 'Pyre'
- Public slot API: save_to_slot/load_from_slot/has_save/delete_save/
  peek_save_metadata. Slots locked: &manual + &autosave

Autosave + UI + Resume toast (Agent C):
- autoload/autosave.gd — new Autosave autoload. Periodic every
  AUTOSAVE_INTERVAL_TICKS = 6000 (~5 in-game min at 20 Hz) + NOTIFICATION_
  APPLICATION_PAUSED (mobile) + NOTIFICATION_WM_WINDOW_FOCUS_OUT (desktop).
  Gated by _busy flag tied to EventBus.save_started/save_finished.
- TopBar extended with SaveBtn (💾) + LoadBtn buttons, 48×48 min hit area
- scenes/ui/load_menu.gd — CanvasLayer slot picker. Reads peek_save_metadata
  to show 'Manual save (Date Time)' / 'Autosave (Date Time)' rows.
  Version-mismatch warning dialog before continuing on older saves.
- scenes/ui/resume_toast.gd — top-center toast. On load_finished(ok=true):
  'Welcome back — N minutes/hours away' for 5s + 0.8s fade.
  On ok=false: 'Load failed (corrupt or version mismatch)'.
- Strings catalog: 14 new keys (ui.save / ui.load / ui.welcome_back_* /
  ui.load_failed etc.)
- main.gd mounts LoadMenu + ResumeToast as runtime CanvasLayer children

MCP runtime verified:
- Saved at tick 1137 → [save] wrote slot 'manual': 113 entities at tick 1137
- Advanced sim to tick 4600 at ULTRA speed (different state)
- load_from_slot(&manual) → [save] applied slot 'manual': 113 entities,
  0 errors, tick=1137, away=34s
- post-load: Sim.tick=1137 (restored), pawns alive=3, all furniture +
  workbenches + crops + walls + floors back in place
- Resume toast fires: [resume_toast] showing — ok=true seconds_away=34
- Autosave on focus-loss verified: [autosave] focus-loss → wrote autosave
- Screenshot shows TopBar with Save + Load buttons + post-load Lone Wolf
  storyteller modal from fresh dawn roll

Known acceptable gaps (deferred to Phase 20 tuning):
- Pawn JobRunner mid-INTERACT/mid-BUILD restarts from toil 0 on reload
  (walk toil round-trips; multi-step interact does not). Pawns lose a few
  seconds of work.
- Workbench bill mid-craft fetch state isn't fully serialized.
- Wolf.target_pawn re-resolution from name string is Agent A's documented
  pattern; Agent B's apply_save respects pawn-restoration ordering so the
  resolution works after pawns are back.

Delegation: 3× gdscript-refactor (Sonnet) agents in parallel; integration
+ MCP verify on Opus.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scenes/ui/top_bar.gd

@@ -1,10 +1,13 @@
 extends CanvasLayer
-## Top-bar HUD: speed/pause buttons and tick counter.
+## Top-bar HUD: speed/pause buttons, tick counter, and save/load controls.
 ##
 ## Buttons call Sim.set_speed(); active button is yellow-tinted.
 ## Tick label updates on every EventBus.sim_tick signal.
 ## Keyboard shortcuts (pause / speed_normal / speed_fast / speed_ultra) are
 ## handled here so the bar is the single owner of speed-input logic.
+##
+## Phase 16: SaveBtn → SaveSystem.save_to_slot(&"manual").
+##           LoadBtn → opens the LoadMenu CanvasLayer (mounted by main.gd).
 
 const ACTIVE_MODULATE := Color(1.2, 1.2, 0.8)
 const IDLE_MODULATE   := Color.WHITE
@@ -13,6 +16,8 @@ const IDLE_MODULATE   := Color.WHITE
 @onready var normal_btn  : Button = $Anchor/ButtonRow/NormalBtn
 @onready var fast_btn    : Button = $Anchor/ButtonRow/FastBtn
 @onready var ultra_btn   : Button = $Anchor/ButtonRow/UltraBtn
+@onready var save_btn    : Button = $Anchor/ButtonRow/SaveBtn
+@onready var load_btn    : Button = $Anchor/ButtonRow/LoadBtn
 @onready var tick_label    : Label  = $Anchor/TickLabel
 @onready var clock_label   : Label  = $Anchor/ClockLabel
 @onready var season_label  : Label  = $Anchor/SeasonLabel
@@ -24,12 +29,17 @@ var _speed_buttons: Dictionary = {}
 var _last_clock_text: String = ""
 var _last_season_text: String = ""
 
+## Injected by main.gd after mount so we don't walk the tree with get_node.
+var load_menu: CanvasLayer = null
+
 
 func _ready() -> void:
 	pause_btn.text   = Strings.t(&"speed.pause")
 	normal_btn.text  = Strings.t(&"speed.normal")
 	fast_btn.text    = Strings.t(&"speed.fast")
 	ultra_btn.text   = Strings.t(&"speed.ultra")
+	save_btn.text    = Strings.t(&"ui.save")
+	load_btn.text    = Strings.t(&"ui.load")
 	tick_label.text   = "(boot)"
 	clock_label.text  = Strings.t(&"clock.format").format({"d": 1, "t": "06:00"})
 	season_label.text = Strings.t(&"season.format").format({"s": Strings.t(&"season.spring"), "d": 1})
@@ -45,11 +55,15 @@ func _ready() -> void:
 	normal_btn.pressed.connect(func() -> void: Sim.set_speed(Sim.Speed.NORMAL))
 	fast_btn.pressed.connect(func() -> void: Sim.set_speed(Sim.Speed.FAST))
 	ultra_btn.pressed.connect(func() -> void: Sim.set_speed(Sim.Speed.ULTRA))
+	save_btn.pressed.connect(_on_save_pressed)
+	load_btn.pressed.connect(_on_load_pressed)
 
 	EventBus.speed_changed.connect(_on_speed_changed)
 	EventBus.sim_tick.connect(_on_sim_tick)
 	EventBus.sim_tick.connect(_on_clock_refresh)
 	EventBus.sim_tick.connect(_on_season_refresh)
+	EventBus.save_started.connect(_on_save_started)
+	EventBus.save_finished.connect(_on_save_finished)
 
 	# Reflect the initial speed state without emitting a signal.
 	_apply_highlight(Sim.current_speed)
@@ -95,3 +109,25 @@ func _on_season_refresh(_n: int) -> void:
 func _apply_highlight(speed: Sim.Speed) -> void:
 	for s: int in _speed_buttons:
 		_speed_buttons[s].modulate = ACTIVE_MODULATE if s == speed else IDLE_MODULATE
+
+
+func _on_save_pressed() -> void:
+	SaveSystem.save_to_slot(&"manual")
+	Audit.log("top_bar", "manual save triggered")
+
+
+func _on_load_pressed() -> void:
+	if load_menu != null and load_menu.has_method("open"):
+		load_menu.open()
+	else:
+		Audit.log("top_bar", "LoadMenu not mounted — skipping open()")
+
+
+func _on_save_started(_slot: StringName) -> void:
+	save_btn.disabled = true
+	save_btn.text = Strings.t(&"ui.saving")
+
+
+func _on_save_finished(_slot: StringName, _ok: bool) -> void:
+	save_btn.disabled = false
+	save_btn.text = Strings.t(&"ui.save")