refactor(shell): author shell scenes as editor-previewable node trees

Move the three shell scenes (SystemDock, NarrationBook, MainWindowShell)
from build-everything-in-_ready() to authored .tscn node trees with the
theme + type-variations set in the editor, so the layout previews and can
be arranged in the Godot editor. Scripts keep only on-load work: @onready
node refs, DM-loop wiring, the dock slide, and binding seed ShellState into
the fixed authored turn-order tokens + consumable slots.

Fixes the dock offset + over-long buttons (now fixed-width DockButtons in a
right-anchored menu). Headless probe: root 1920x1080, world/book split
1180/740, dock at the world's right edge — no collapse. Suite 138/138.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client/scripts/ui/shell/narration_book.gd

@@ -5,75 +5,30 @@ extends Control
 ## written back to the canon log (§11). Prose-only this milestone: the numbered
 ## response choices and the "describe your own action" line are faithful but inert
 ## (no action system yet); one in-world refire affordance re-runs narration.
+##
+## Layout is authored in NarrationBook.tscn (editor-previewable). This script only
+## binds the header, drives the narrate loop, and swaps prose text.
 
 var last_degraded: bool = false
 
 var _service: DmService
 var _log: CanonLog
 var _state: ShellState
-var _header: Label
-var _prose: RichTextLabel
-var _status: Label
-var _refire: Button
-var _degraded_tag: Label
 var _indicator: ConsideringIndicator
 
+@onready var _header: Label = $Margin/Col/Header
+@onready var _prose: RichTextLabel = $Margin/Col/Prose
+@onready var _degraded_tag: Label = $Margin/Col/DegradedTag
+@onready var _refire: Button = $Margin/Col/Refire
+@onready var _status: Label = $Margin/Col/Status
+
 
 func _ready() -> void:
-	var col := VBoxContainer.new()
-	col.set_anchors_preset(Control.PRESET_FULL_RECT)
-	col.add_theme_constant_override("separation", 18)
-	add_child(col)
-
-	_header = Label.new()
-	_header.theme_type_variation = ThemeKeys.ACCENT
-	col.add_child(_header)
-
-	_prose = RichTextLabel.new()
-	_prose.bbcode_enabled = true
-	_prose.fit_content = true
-	_prose.size_flags_vertical = Control.SIZE_EXPAND_FILL
-	_prose.custom_minimum_size = Vector2(660, 320)
-	col.add_child(_prose)
-
-	_degraded_tag = Label.new()
-	_degraded_tag.theme_type_variation = ThemeKeys.MONO
-	_degraded_tag.text = "THE MASTER'S VOICE COMES THIN"  # shown only when degraded
-	_degraded_tag.visible = false
-	col.add_child(_degraded_tag)
-
-	# Faithful-but-inert placeholders (charter: prose-only this milestone).
-	var prompt := Label.new()
-	prompt.theme_type_variation = ThemeKeys.ACCENT
-	prompt.text = "▸ Your turn. What do you do?"
-	col.add_child(prompt)
-	for line in [
-			"1 · Pay the fence double and keep your hand where he can see it",
-			"2 · Draw your blade — he's closer than his guards",
-			"3 · Lie — tell him the rest is coming with your dwarf"]:
-		var choice := Button.new()
-		choice.theme_type_variation = ThemeKeys.PARCHMENT_BUTTON
-		choice.text = line
-		choice.disabled = true  # inert until combat/dialogue give choices meaning
-		col.add_child(choice)
-	var free_text := Label.new()
-	free_text.theme_type_variation = ThemeKeys.MONO
-	free_text.text = "⌨  …or describe your own action"
-	col.add_child(free_text)
-
-	# The one live control: refire the narration.
-	_refire = Button.new()
-	_refire.theme_type_variation = ThemeKeys.PARCHMENT_BUTTON
-	_refire.text = "▸ The Master continues…"
-	_refire.pressed.connect(_on_refire_pressed)
-	col.add_child(_refire)
-
-	_status = Label.new()
-	_status.theme_type_variation = ThemeKeys.MONO
-	col.add_child(_status)
-
+	# The considering indicator is a non-visual Node (a Timer + label driver), so
+	# it stays code-created rather than authored in the scene.
 	_indicator = ConsideringIndicator.new()
 	add_child(_indicator)
+	_refire.pressed.connect(_on_refire_pressed)
 
 
 func setup(service: DmService, log: CanonLog, state: ShellState) -> void: