Frames the next core-panels work for a fresh session, after B.1 (drag spine) +
B.2 (toolbar reorder/remove + wire) + toolbar collapse merged this session.
Three sub-phases in order: (A) minimal window manager (open/close + I-key toggle;
UiHost has no open/close API today, windows are always-on); (B) inventory window
(Stream C, synthesis §4 — UiItemList grid + sub-window mount + wire gaps +
InventoryController; the drag SOURCE that closes B.2's drag-from-inventory via a
SourceKind==Inventory branch in ToolbarController.HandleDropRelease); (C) paperdoll
UiViewport (Type 0xD) + Core→App IUiViewportRenderer seam, heaviest, last. Spell
bar deferred. Reuse the shipped spine/ShortcutStore/wire. Paste-able new-session
prompt + MEMORY index line inside.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
