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/main/main.gd

@@ -8,9 +8,15 @@ extends Node2D
 ## Phase 15 — StorytellerBanner and StorytellerModal are runtime-instantiated
 ## here (same pattern as world.gd's BeautySystem / DirtinessSystem). Both are
 ## CanvasLayer nodes so they draw above the world regardless of scene-tree order.
+##
+## Phase 16 — LoadMenu (layer 25) and ResumeToast (layer 22) are runtime-
+## instantiated here. LoadMenu ref is injected into TopBar so the Load button
+## can call open() without a get_node("/root/…") call.
 
 const STORYTELLER_BANNER_SCRIPT: Script = preload("res://scenes/ui/storyteller_banner.gd")
-const STORYTELLER_MODAL_SCRIPT: Script = preload("res://scenes/ui/storyteller_modal.gd")
+const STORYTELLER_MODAL_SCRIPT: Script  = preload("res://scenes/ui/storyteller_modal.gd")
+const LOAD_MENU_SCRIPT: Script          = preload("res://scenes/ui/load_menu.gd")
+const RESUME_TOAST_SCRIPT: Script       = preload("res://scenes/ui/resume_toast.gd")
 
 
 func _ready() -> void:
@@ -23,6 +29,7 @@ func _ready() -> void:
 	assert(EventBus != null, "EventBus autoload missing")
 	assert(Strings != null, "Strings autoload missing")
 	assert(SaveSystem != null, "SaveSystem autoload missing")
+	assert(Autosave != null, "Autosave autoload missing")
 
 	# Phase 15 — Storyteller UI layers. Runtime-instantiated so no .tscn edit is
 	# needed. CanvasLayer ensures correct draw order above World/TopBar regardless
@@ -38,3 +45,24 @@ func _ready() -> void:
 	add_child(modal)
 
 	Audit.log("main", "Phase 15 — StorytellerBanner + StorytellerModal mounted.")
+
+	# Phase 16 — Save/Load UI layers.
+	var resume_toast := CanvasLayer.new()
+	resume_toast.set_script(RESUME_TOAST_SCRIPT)
+	resume_toast.name = "ResumeToast"
+	add_child(resume_toast)
+
+	var load_menu := CanvasLayer.new()
+	load_menu.set_script(LOAD_MENU_SCRIPT)
+	load_menu.name = "LoadMenu"
+	add_child(load_menu)
+
+	# Inject LoadMenu ref into TopBar so the Load button can call open()
+	# without reaching into the scene tree by path.
+	var top_bar = get_node_or_null("TopBar")
+	if top_bar != null and top_bar.has_method("_ready"):
+		top_bar.load_menu = load_menu
+	elif top_bar != null:
+		top_bar.load_menu = load_menu
+
+	Audit.log("main", "Phase 16 — LoadMenu + ResumeToast mounted.")