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/model/nav_test.go

@@ -9,7 +9,7 @@ import (
 func TestNavTreeHasExpectedRoots(t *testing.T) {
 	tree := model.DefaultNavTree()
 	roots := tree.RootLabels()
-	want := []string{"Projects", "Calendar", "CRM", "Mail", "Users"}
+	want := []string{"Projects", "Tasks", "By project", "Calendar", "CRM", "Mail", "Users"}
 	if len(roots) != len(want) {
 		t.Fatalf("roots=%v want %v", roots, want)
 	}
@@ -22,42 +22,79 @@ func TestNavTreeHasExpectedRoots(t *testing.T) {
 
 func TestNavExpandCollapse(t *testing.T) {
 	tree := model.DefaultNavTree()
-	if !tree.IsExpandable(0) {
-		t.Fatal("Projects should be expandable")
+	var crm int = -1
+	for i := 0; i < tree.VisibleCount(); i++ {
+		n, ok := tree.NodeAtVisible(i)
+		if ok && n.Label == "CRM" {
+			crm = i
+			break
+		}
 	}
-	tree.ToggleExpand(0)
-	if !tree.IsExpanded(0) {
-		t.Fatal("Projects should expand")
+	if crm < 0 {
+		t.Fatal("CRM node not found")
 	}
-	tree.ToggleExpand(0)
-	if tree.IsExpanded(0) {
-		t.Fatal("Projects should collapse")
+	if !tree.IsExpandable(crm) {
+		t.Fatal("CRM should be expandable")
+	}
+	tree.ToggleExpand(crm)
+	if !tree.IsExpanded(crm) {
+		t.Fatal("CRM should expand")
+	}
+	tree.ToggleExpand(crm)
+	if tree.IsExpanded(crm) {
+		t.Fatal("CRM should collapse")
 	}
 }
 
-func TestNavLeafReturnsListSpec(t *testing.T) {
+func TestNavCalendarLeafReturnsListSpec(t *testing.T) {
 	tree := model.DefaultNavTree()
-	tree.ToggleExpand(0) // Projects
-	tree.ToggleExpand(1) // Browse
-	// Find "All projects" leaf cursor
 	var found int = -1
 	for i := 0; i < tree.VisibleCount(); i++ {
 		n, ok := tree.NodeAtVisible(i)
-		if ok && n.List != nil && n.List.Subject == model.SubjectProjects {
+		if ok && n.Label == "Calendar" {
 			found = i
 			break
 		}
 	}
 	if found < 0 {
-		t.Fatal("all projects leaf not found")
+		t.Fatal("Calendar node not found")
 	}
 	tree.SetCursor(found)
 	spec, ok := tree.CurrentListSpec()
-	if !ok || spec.Subject != model.SubjectProjects {
+	if !ok || spec.Subject != model.SubjectCalendar {
 		t.Fatalf("spec=%v ok=%v", spec, ok)
 	}
 }
 
+func TestNavProjectsLeafReturnsListSpec(t *testing.T) {
+	tree := model.DefaultNavTree()
+	tree.SetCursor(0)
+	spec, ok := tree.CurrentListSpec()
+	if !ok || spec.Subject != model.SubjectProjects {
+		t.Fatalf("projects spec=%v ok=%v", spec, ok)
+	}
+}
+
+func TestNavTasksLeafReturnsListSpec(t *testing.T) {
+	tree := model.DefaultNavTree()
+	var found int = -1
+	for i := 0; i < tree.VisibleCount(); i++ {
+		n, ok := tree.NodeAtVisible(i)
+		if ok && n.Label == "Tasks" {
+			found = i
+			break
+		}
+	}
+	if found < 0 {
+		t.Fatal("Tasks node not found")
+	}
+	tree.SetCursor(found)
+	spec, ok := tree.CurrentListSpec()
+	if !ok || spec.Subject != model.SubjectTasks {
+		t.Fatalf("tasks spec=%v ok=%v", spec, ok)
+	}
+}
+
 func TestPrevFocusPane(t *testing.T) {
 	if got := model.PrevFocusPane(model.FocusList); got != model.FocusMenu {
 		t.Fatalf("got %v", got)
@@ -67,6 +104,41 @@ func TestPrevFocusPane(t *testing.T) {
 	}
 }
 
+func TestNavFilterByLabel(t *testing.T) {
+	tree := model.DefaultNavTree()
+	tree.SetFilter("inbox")
+	found := false
+	for i := 0; i < tree.VisibleCount(); i++ {
+		n, ok := tree.NodeAtVisible(i)
+		if ok && n.Label == "Inbox" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatal("Inbox should remain visible when filtering mail")
+	}
+	for i := 0; i < tree.VisibleCount(); i++ {
+		n, ok := tree.NodeAtVisible(i)
+		if ok && n.Label == "Calendar" {
+			t.Fatal("Calendar should be hidden when filtering inbox")
+		}
+	}
+}
+
+func TestNavClearFilterRestoresTree(t *testing.T) {
+	tree := model.DefaultNavTree()
+	before := tree.VisibleCount()
+	tree.SetFilter("zzz-no-match")
+	if tree.VisibleCount() >= before {
+		t.Fatalf("filter should shrink visible nodes")
+	}
+	tree.ClearFilter()
+	if tree.VisibleCount() != before {
+		t.Fatalf("clear filter should restore visible count")
+	}
+}
+
 func TestActionsForContact(t *testing.T) {
 	acts := model.ActionsFor(model.KindContact)
 	if len(acts) != 1 || acts[0].ID != model.ActionDelete {