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>