feat(office): mail preview, infinite scroll, pane resize, and scrollbars

Polish the office TUI with proportional pane layout, drag resize, live
filtering, HTML mail preview, paginated mail lists, overflow scrollbars,
flattened navigation, and project save/status fixes; add UpdateProjectStatus.

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

cmd/office/ui/layout_resize.go

@@ -0,0 +1,203 @@
+package ui
+
+import (
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+const (
+	minPaneOuterWidth = 14
+	resizeHitSlop     = 1
+)
+
+type paneResizeState struct {
+	active   bool
+	divider  int
+	anchorX  int
+	anchorPW PaneWidths
+}
+
+// FitPaneWidths scales stored pane widths to fill total width for visible panes.
+func FitPaneWidths(total int, vis PaneVisibility, sizes PaneWidths) PaneWidths {
+	if total < 1 {
+		total = 80
+	}
+	out := PaneWidths{Visibility: vis}
+	if countVisible(vis) == 0 {
+		return LayoutWidths(total, vis)
+	}
+	sum := 0
+	if vis.Menu {
+		sum += sizes.Menu
+	}
+	if vis.List {
+		sum += sizes.List
+	}
+	if vis.Detail {
+		sum += sizes.Detail
+	}
+	if sum <= 0 {
+		return LayoutWidths(total, vis)
+	}
+	assign := func(visible bool, stored int) int {
+		if !visible {
+			return 0
+		}
+		return stored * total / sum
+	}
+	out.Menu = assign(vis.Menu, sizes.Menu)
+	out.List = assign(vis.List, sizes.List)
+	out.Detail = assign(vis.Detail, sizes.Detail)
+	fixPaneWidthSum(&out, total)
+	return out
+}
+
+func fixPaneWidthSum(pw *PaneWidths, total int) {
+	if pw == nil || total < 1 {
+		return
+	}
+	type slot struct {
+		visible bool
+		width   *int
+	}
+	slots := []slot{
+		{pw.Visibility.Menu, &pw.Menu},
+		{pw.Visibility.List, &pw.List},
+		{pw.Visibility.Detail, &pw.Detail},
+	}
+	sum := 0
+	var last *int
+	for _, s := range slots {
+		if !s.visible {
+			continue
+		}
+		sum += *s.width
+		last = s.width
+	}
+	if last == nil {
+		return
+	}
+	*last += total - sum
+	if *last < minPaneOuterWidth {
+		*last = minPaneOuterWidth
+	}
+}
+
+// DividerPositions returns x coordinates of vertical pane separators.
+func DividerPositions(pw PaneWidths) []int {
+	var out []int
+	x := 0
+	if pw.Visibility.Menu {
+		x += pw.Menu
+		if pw.Visibility.List || pw.Visibility.Detail {
+			out = append(out, x)
+		}
+	}
+	if pw.Visibility.List {
+		x += pw.List
+		if pw.Visibility.Detail {
+			out = append(out, x)
+		}
+	}
+	return out
+}
+
+// DividerAt returns the divider index under x, or -1.
+func DividerAt(x int, pw PaneWidths) int {
+	for i, pos := range DividerPositions(pw) {
+		if x >= pos-resizeHitSlop && x <= pos+resizeHitSlop {
+			return i
+		}
+	}
+	return -1
+}
+
+// DragPaneDivider adjusts adjacent pane widths by deltaX pixels.
+func DragPaneDivider(pw PaneWidths, divider, deltaX int) (PaneWidths, bool) {
+	if deltaX == 0 {
+		return pw, false
+	}
+	changed := false
+	switch divider {
+	case 0:
+		if pw.Visibility.Menu && pw.Visibility.List {
+			if resizePair(&pw.Menu, &pw.List, deltaX) {
+				changed = true
+			}
+		} else if pw.Visibility.Menu && pw.Visibility.Detail {
+			if resizePair(&pw.Menu, &pw.Detail, deltaX) {
+				changed = true
+			}
+		}
+	case 1:
+		if pw.Visibility.List && pw.Visibility.Detail {
+			if resizePair(&pw.List, &pw.Detail, deltaX) {
+				changed = true
+			}
+		}
+	}
+	return pw, changed
+}
+
+func resizePair(left, right *int, delta int) bool {
+	if left == nil || right == nil {
+		return false
+	}
+	newLeft := *left + delta
+	newRight := *right - delta
+	if newLeft < minPaneOuterWidth || newRight < minPaneOuterWidth {
+		return false
+	}
+	*left = newLeft
+	*right = newRight
+	return true
+}
+
+func (m Model) paneResizeMaxY() int {
+	return m.paneHeight() + 1
+}
+
+func (m *Model) handlePaneResizeMouse(msg tea.MouseMsg) bool {
+	if msg.Y >= m.paneResizeMaxY() {
+		if m.resize.active && msg.Action == tea.MouseActionRelease {
+			m.resize.active = false
+			return true
+		}
+		return false
+	}
+
+	pw := m.paneLayout()
+	switch msg.Action {
+	case tea.MouseActionPress:
+		if msg.Button != tea.MouseButtonLeft {
+			return false
+		}
+		if div := DividerAt(msg.X, pw); div >= 0 {
+			m.paneSizes = pw
+			m.customPaneLayout = true
+			m.resize = paneResizeState{
+				active:   true,
+				divider:  div,
+				anchorX:  msg.X,
+				anchorPW: pw,
+			}
+			return true
+		}
+	case tea.MouseActionRelease:
+		if m.resize.active {
+			m.resize.active = false
+			return true
+		}
+	case tea.MouseActionMotion:
+		if m.resize.active {
+			delta := msg.X - m.resize.anchorX
+			next, ok := DragPaneDivider(m.resize.anchorPW, m.resize.divider, delta)
+			if ok {
+				m.paneSizes = next
+				m.layoutViewports()
+				m.syncAllContent()
+			}
+			return true
+		}
+	}
+	return m.resize.active
+}