feat(office): table detail panes and Alt+1/2/3 layout toggles

Add spreadsheet-style list, split detail pane with forms and document preview,
and Alt+1/2/3 to show/hide panes with even width distribution.

Co-authored-by: Cursor <cursoragent@cursor.com>

cmd/office/ui/layout.go

@@ -0,0 +1,129 @@
+package ui
+
+import "github.com/eslider/go-onlyoffice/cmd/office/model"
+
+// PaneVisibility controls which columns are shown.
+type PaneVisibility struct {
+	Menu, List, Detail bool
+}
+
+// PaneWidths is outer lipgloss width per column (sums to terminal width).
+type PaneWidths struct {
+	Menu, List, Detail int
+	Visibility         PaneVisibility
+}
+
+func defaultPaneVisibility() PaneVisibility {
+	return PaneVisibility{Menu: true, List: true, Detail: true}
+}
+
+// LayoutWidths splits total terminal width evenly across visible panes.
+func LayoutWidths(total int, vis PaneVisibility) PaneWidths {
+	if total < 1 {
+		total = 80
+	}
+	v := vis
+	n := countVisible(v)
+	if n == 0 {
+		v = defaultPaneVisibility()
+		n = 3
+	}
+	base := total / n
+	rem := total % n
+	out := PaneWidths{Visibility: v}
+	if v.Menu {
+		out.Menu = base
+		if rem > 0 {
+			out.Menu++
+			rem--
+		}
+	}
+	if v.List {
+		out.List = base
+		if rem > 0 {
+			out.List++
+			rem--
+		}
+	}
+	if v.Detail {
+		out.Detail = base
+		if rem > 0 {
+			out.Detail++
+			rem--
+		}
+	}
+	return out
+}
+
+func countVisible(v PaneVisibility) int {
+	n := 0
+	if v.Menu {
+		n++
+	}
+	if v.List {
+		n++
+	}
+	if v.Detail {
+		n++
+	}
+	return n
+}
+
+// NextVisibleFocus cycles focus forward, skipping hidden panes.
+func NextVisibleFocus(cur model.FocusPane, vis PaneVisibility) model.FocusPane {
+	order := []model.FocusPane{model.FocusMenu, model.FocusList, model.FocusPreview}
+	start := 0
+	for i, p := range order {
+		if p == cur {
+			start = i
+			break
+		}
+	}
+	for step := 1; step <= len(order); step++ {
+		p := order[(start+step)%len(order)]
+		if paneVisible(p, vis) {
+			return p
+		}
+	}
+	return cur
+}
+
+// PrevVisibleFocus cycles focus backward, skipping hidden panes.
+func PrevVisibleFocus(cur model.FocusPane, vis PaneVisibility) model.FocusPane {
+	order := []model.FocusPane{model.FocusMenu, model.FocusList, model.FocusPreview}
+	start := 0
+	for i, p := range order {
+		if p == cur {
+			start = i
+			break
+		}
+	}
+	for step := 1; step <= len(order); step++ {
+		p := order[(start-step+len(order))%len(order)]
+		if paneVisible(p, vis) {
+			return p
+		}
+	}
+	return cur
+}
+
+func paneVisible(p model.FocusPane, vis PaneVisibility) bool {
+	switch p {
+	case model.FocusMenu:
+		return vis.Menu
+	case model.FocusList:
+		return vis.List
+	default:
+		return vis.Detail
+	}
+}
+
+func firstVisibleFocus(vis PaneVisibility) model.FocusPane {
+	if vis.Menu {
+		return model.FocusMenu
+	}
+	if vis.List {
+		return model.FocusList
+	}
+	return model.FocusPreview
+}