fix(ui): port retail window control feedback

Map synthetic move and resize affordances to the exact DAT cursors, make chat top chrome movable, and replace stale primary-panel height caps with a dynamic screen-edge constraint. This keeps the retained wrapper adaptation aligned with retail Dragbar/Resizebar behavior.

docs/research/2026-07-17-retail-window-control-cursor-pseudocode.md

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+# Retail window-control cursor pseudocode
+
+Date: 2026-07-17
+
+## Question
+
+Which cursors does the end-of-retail client show while hovering or operating
+window dragbars and resizebars, and how are they selected?
+
+## Named-retail mechanism
+
+### Widget cursor ownership
+
+```text
+MediaMachine::Update_Cursor(owner, cursorMedia)       // 0x00465A80
+    if cursorMedia.file is valid
+        owner.SetCursor(file, hotspotX, hotspotY)
+    else
+        owner.UnSetCursor()
+
+UIElement::SetCursor(file, hotspotX, hotspotY)        // 0x0045FF50
+    m_cursorDID = file
+    m_cursorHotX = hotspotX
+    m_cursorHotY = hotspotY
+    UIElementManager.CheckCursor()
+
+UIElementManager::CheckCursor()                       // 0x0045ABF0
+    if mouseCapture != null and mouseCapture.HasCursor()
+        apply mouseCapture cursor
+    else if lastEntered != null and lastEntered.HasCursor()
+        apply lastEntered cursor
+    else
+        apply ClientUISystem default cursor
+```
+
+The important ownership rule is that the captured widget wins. A resize or
+move cursor therefore remains visible after the pointer leaves the original
+five-pixel control while the button is still held.
+
+### Window controls
+
+```text
+UIElement_Resizebar::StartMouseResizing(point)        // 0x0046B7E0
+    parent = GetParent()
+    edge = authored Left/Right/Top/Bottom attributes
+    m_mousePressed = true
+    parent.StartResizing(edge, point.x, point.y)
+    SetState(Pressed)
+
+UIElement_Resizebar::StopMouseResizing()              // 0x0046B8C0
+    SetState(Normal)
+    m_mousePressed = false
+    GetParent().StopResizing()
+
+UIElement_Dragbar::StartMouseMoving(message)          // 0x0046C760
+    if primary mouse button and parent is not already moving/resizing
+        m_mousePressed = true
+        parent.StartMovement(message.windowX, message.windowY)
+        SetState(Pressed)
+
+UIElement_Dragbar::StopMouseMoving(message)           // 0x0046C7C0
+    if pressed and primary mouse button
+        SetState(Normal)
+        m_mousePressed = false
+        GetParent().StopMovement()
+```
+
+Dragbar and Resizebar do not synthesize OS cursors in these methods. Their
+LayoutDesc state media supplies `MD_Data_Cursor`; the generic
+`MediaMachine::Update_Cursor` path above installs it on the element.
+
+## Installed end-of-retail DAT oracle
+
+The production LayoutDesc records and portal DAT resolve these direct cursor
+surfaces, all with hotspot `(16, 16)` pixels:
+
+| Intent | RenderSurface DID | Observed authored use |
+|---|---:|---|
+| Move window | `0x06006119` | Type-2 Dragbar controls |
+| Resize vertically | `0x06005E66` | horizontal Type-9 Resizebar (main chat top edge and combat bottom edge) |
+| Resize horizontally | `0x06006128` | vertical Type-9 Resizebar |
+| Resize NW-SE | `0x06006126` | top-left and bottom-right Type-9 corners |
+| Resize NE-SW | `0x06006127` | bottom-left / opposite diagonal Type-9 corner |
+
+All five surfaces are 32×32 `PFID_A8R8G8B8` cursor images. Representative
+LayoutDesc fixtures independently preserve the same media:
+
+- main chat `0x21000006`, element `0x1000000F`: vertical cursor
+  `0x06005E66` at `(16,16)`;
+- combat `0x21000073`, Dragbar `0x100006AE`: move cursor
+  `0x06006119` at `(16,16)`;
+- combat corner/edge Resizebars: `0x06006126..0x06006128`.
+
+`DatReaderWriter` supplies these cursor records through the existing
+LayoutDesc media decode. WorldBuilder's backend exposes the same architectural
+boundary (`SetCursor(cursorDataId, hotspot)`) but leaves it unimplemented; it
+does not provide a competing behavior interpretation.
+
+## acdream root cause and port
+
+`UiRoot` already computes the active or hovered resize edges and window-move
+ownership. `CursorFeedbackController` already translates those states into
+`WindowMove`, `ResizeHorizontal`, `ResizeVertical`, and the two diagonal
+semantic kinds. However, `RetailCursorManager` renders only a valid
+`UiCursorMedia` override or the `ClientUISystem` global cursor. The semantic
+window-control kind was never converted to media, so synthetic wrapper borders
+and whole-window drag regions retained the normal pointer.
+
+Port shape:
+
+```text
+ResolveWindowControlCursor(kind):
+    WindowMove         -> 0x06006119 @ (16,16)
+    ResizeHorizontal   -> 0x06006128 @ (16,16)
+    ResizeVertical     -> 0x06005E66 @ (16,16)
+    ResizeDiagonalNWSE -> 0x06006126 @ (16,16)
+    ResizeDiagonalNESW -> 0x06006127 @ (16,16)
+
+UpdateCursor(root):
+    kind = resolve semantic interaction state
+    authored = captured-or-hovered element cursor, using retail precedence
+
+    if a synthetic resize edge owns the pointer or a resize/move operation owns capture
+        cursor = ResolveWindowControlCursor(kind)
+    else if authored is valid
+        cursor = authored
+    else
+        cursor = ResolveWindowControlCursor(kind)
+
+    render cursor; otherwise retain the ClientUISystem global cursor
+```
+
+Authored widget media therefore remains the first hover-time oracle. The
+shared fallback exists for retained wrapper borders and the accepted IA-12
+whole-window drag adaptation, which have no authored Dragbar/Resizebar child.
+Once a synthetic operation starts, its control cursor wins just as retail's
+captured Dragbar or Resizebar wins.