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/resume_toast.gd

@@ -0,0 +1,124 @@
+class_name ResumeToast extends CanvasLayer
+## Phase 16 — "Welcome back / Load failed" toast.
+##
+## Layer 22 — above Modal (20) but below LoadMenu (25).
+## Listens to EventBus.load_finished.
+## On ok=true:  "Welcome back — away N minutes/hours" for SHOW_DURATION_SEC, then fades.
+## On ok=false: "Load failed (corrupt or version mismatch)" — same fade cadence.
+
+const SHOW_DURATION_SEC: float = 5.0
+const FADE_DURATION_SEC: float = 0.8
+
+var _root: Control = null
+var _label: Label = null
+var _show_timer: Timer = null
+
+var _fade_time: float = 0.0
+var _fading: bool = false
+
+
+func _ready() -> void:
+	layer = 22
+	_build_ui()
+	_root.visible = false
+	EventBus.load_finished.connect(_on_load_finished)
+	Audit.log("resume_toast", "ResumeToast ready")
+
+
+func _exit_tree() -> void:
+	if EventBus.load_finished.is_connected(_on_load_finished):
+		EventBus.load_finished.disconnect(_on_load_finished)
+
+
+func _process(delta: float) -> void:
+	if not _fading:
+		return
+	_fade_time -= delta
+	if _fade_time <= 0.0:
+		_fading = false
+		_root.visible = false
+		_root.modulate = Color.WHITE
+		return
+	_root.modulate.a = clampf(_fade_time / FADE_DURATION_SEC, 0.0, 1.0)
+
+
+# ── UI construction ───────────────────────────────────────────────────────────
+
+func _build_ui() -> void:
+	# Top-center strip — sits just below the top bar.
+	_root = Control.new()
+	_root.name = "ToastRoot"
+	_root.set_anchors_preset(Control.PRESET_TOP_WIDE)
+	_root.custom_minimum_size = Vector2(0, 56)
+	_root.offset_top = 56       # below the 48 px top bar + a little gap
+	_root.offset_bottom = 112
+	_root.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	add_child(_root)
+
+	var panel := PanelContainer.new()
+	panel.name = "Panel"
+	panel.set_anchors_preset(Control.PRESET_CENTER_TOP)
+	panel.custom_minimum_size = Vector2(400, 48)
+	panel.offset_left  = -200
+	panel.offset_right = 200
+	panel.offset_top   = 0
+	panel.offset_bottom = 48
+	panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_root.add_child(panel)
+
+	_label = Label.new()
+	_label.name = "ToastLabel"
+	_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	_label.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
+	_label.autowrap_mode = TextServer.AUTOWRAP_OFF
+	panel.add_child(_label)
+
+	_show_timer = Timer.new()
+	_show_timer.name = "ShowTimer"
+	_show_timer.one_shot = true
+	_show_timer.wait_time = SHOW_DURATION_SEC
+	_show_timer.timeout.connect(_start_fade)
+	add_child(_show_timer)
+
+
+# ── event handling ────────────────────────────────────────────────────────────
+
+func _on_load_finished(_slot: StringName, ok: bool, real_seconds_away: int) -> void:
+	if ok:
+		_label.text = _format_welcome(real_seconds_away)
+	else:
+		_label.text = Strings.t(&"ui.load_failed")
+
+	_root.modulate = Color.WHITE
+	_root.visible = true
+	_fading = false
+	_show_timer.start()
+	Audit.log("resume_toast", "showing — ok=%s seconds_away=%d" % [ok, real_seconds_away])
+
+
+func _start_fade() -> void:
+	_fading = true
+	_fade_time = FADE_DURATION_SEC
+
+
+# ── helpers ───────────────────────────────────────────────────────────────────
+
+func _format_welcome(seconds_away: int) -> String:
+	var duration_str: String
+	if seconds_away < 120:
+		# Less than 2 minutes — show as "1 minute"
+		duration_str = Strings.t(&"ui.welcome_back_min").format({"n": 1})
+	elif seconds_away < 3600:
+		# Under an hour — show in minutes.
+		var mins: int = seconds_away / 60
+		var key: StringName = &"ui.welcome_back_min" if mins == 1 else &"ui.welcome_back_mins"
+		duration_str = Strings.t(key).format({"n": mins})
+	elif seconds_away < 7200:
+		# 1–2 hours exactly → singular.
+		duration_str = Strings.t(&"ui.welcome_back_hour").format({"n": 1})
+	else:
+		var hrs: int = seconds_away / 3600
+		var key: StringName = &"ui.welcome_back_hour" if hrs == 1 else &"ui.welcome_back_hours"
+		duration_str = Strings.t(key).format({"n": hrs})
+
+	return Strings.t(&"ui.welcome_back").format({"n": duration_str})