Add ticket time tracking with reports and entry management.

Support start/stop timer, manual durations, grouped reports, and per-ticket edit/delete of time entries with undo.

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

internal/command/time_cmds_test.go

@@ -0,0 +1,75 @@
+package command_test
+
+import (
+	"testing"
+	"time"
+
+	"task/internal/command"
+	"task/internal/ticket"
+)
+
+func TestUpdateTimeEntryUndo(t *testing.T) {
+	dir := t.TempDir()
+	store := ticket.NewJSONTimeStore(dir)
+	h := command.NewHistory()
+
+	created, err := store.Create(ticket.TimeEntry{
+		TicketID:  "t1",
+		ProjectID: "inbox",
+		Start:     time.Now().UTC().Add(-time.Hour),
+		Duration:  time.Hour,
+		Source:    ticket.SourceManual,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	after := created
+	after.Duration = 30 * time.Minute
+	after.End = after.Start.Add(after.Duration)
+	if err := h.Do(&command.UpdateTimeEntry{Store: store, Before: created, After: after}); err != nil {
+		t.Fatal(err)
+	}
+	list, _ := store.ListByTicket("t1")
+	if len(list) != 1 || list[0].Duration != 30*time.Minute {
+		t.Fatalf("after update: %+v", list)
+	}
+	if err := h.Undo(); err != nil {
+		t.Fatal(err)
+	}
+	list, _ = store.ListByTicket("t1")
+	if len(list) != 1 || list[0].Duration != time.Hour {
+		t.Fatalf("after undo: %+v", list)
+	}
+}
+
+func TestRemoveTimeEntryUndo(t *testing.T) {
+	dir := t.TempDir()
+	store := ticket.NewJSONTimeStore(dir)
+	h := command.NewHistory()
+
+	created, err := store.Create(ticket.TimeEntry{
+		TicketID:  "t1",
+		ProjectID: "inbox",
+		Start:     time.Now().UTC(),
+		Duration:  15 * time.Minute,
+		Source:    ticket.SourceTimer,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := h.Do(&command.RemoveTimeEntry{Store: store, Snapshot: created}); err != nil {
+		t.Fatal(err)
+	}
+	list, _ := store.List()
+	if len(list) != 0 {
+		t.Fatalf("expected empty after remove, got %d", len(list))
+	}
+	if err := h.Undo(); err != nil {
+		t.Fatal(err)
+	}
+	list, _ = store.List()
+	if len(list) != 1 || list[0].ID != created.ID {
+		t.Fatalf("after undo: %+v", list)
+	}
+}