Allow editing time entry start and end in TUI and web.

Duration is derived from the range so timer sessions can be corrected after the fact.

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

internal/ui/views/timeedit_test.go

@@ -0,0 +1,34 @@
+package views
+
+import (
+	"testing"
+	"time"
+
+	"task/internal/ticket"
+)
+
+func TestTimeEditFormParse(t *testing.T) {
+	start := time.Date(2024, 6, 1, 9, 0, 0, 0, time.Local)
+	end := start.Add(90 * time.Minute)
+	f := NewTimeEditForm(ticket.TimeEntry{Start: start, End: end, Duration: 90 * time.Minute}, 80)
+
+	gotStart, gotEnd, err := f.Parse()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !gotStart.Equal(start.UTC()) {
+		t.Fatalf("start: got %v want %v", gotStart, start.UTC())
+	}
+	if !gotEnd.Equal(end.UTC()) {
+		t.Fatalf("end: got %v want %v", gotEnd, end.UTC())
+	}
+}
+
+func TestTimeEditFormRejectsBadRange(t *testing.T) {
+	start := time.Date(2024, 6, 1, 9, 0, 0, 0, time.Local)
+	f := NewTimeEditForm(ticket.TimeEntry{Start: start, End: start, Duration: time.Minute}, 80)
+	f.Inputs[FieldTimeEnd].SetValue(start.Format(timeEditLayout))
+	if _, _, err := f.Parse(); err == nil {
+		t.Fatal("expected error for end == start")
+	}
+}