feat(cli): add nib add + nib ls commands

Default command delegation: `nib "..."` routes to `nib add`. Capture
bar parses grammar, creates entities. `nib ls` lists with date
grouping, tag filter, 48h default window. Display glyphs for all
entity types.

cmd/ls.go

@@ -0,0 +1,131 @@
+package cmd
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/lerko/nib/internal/db"
+	"github.com/lerko/nib/internal/display"
+	"github.com/spf13/cobra"
+)
+
+var (
+	lsTag  string
+	lsDate string
+	lsAll  bool
+)
+
+var lsCmd = &cobra.Command{
+	Use:   "ls",
+	Short: "list entities in stream order",
+	RunE:  runLs,
+}
+
+func init() {
+	lsCmd.Flags().StringVar(&lsTag, "tag", "", "filter by tag")
+	lsCmd.Flags().StringVar(&lsDate, "date", "", "filter by date (YYYY-MM-DD)")
+	lsCmd.Flags().BoolVar(&lsAll, "all", false, "include deleted entities")
+}
+
+func runLs(_ *cobra.Command, _ []string) error {
+	store, err := openStore()
+	if err != nil {
+		return err
+	}
+	defer store.Close()
+
+	p := db.DefaultListParams()
+	p.IncludeDeleted = lsAll
+
+	if lsTag != "" {
+		p.Tag = &lsTag
+	}
+	if lsDate != "" {
+		p.Date = &lsDate
+	} else {
+		since := time.Now().UTC().Add(-48 * time.Hour)
+		p.Since = &since
+	}
+
+	entities, err := store.List(p)
+	if err != nil {
+		return err
+	}
+
+	if len(entities) == 0 {
+		return nil
+	}
+
+	groups := groupByDate(entities)
+	for _, g := range groups {
+		fmt.Printf("── %s ──\n", g.label)
+		for _, e := range g.entities {
+			printEntity(e)
+		}
+		fmt.Println()
+	}
+
+	return nil
+}
+
+type dateGroup struct {
+	label    string
+	entities []*db.Entity
+}
+
+func groupByDate(entities []*db.Entity) []dateGroup {
+	var groups []dateGroup
+	var current *dateGroup
+
+	for _, e := range entities {
+		label := formatDateLabel(e.CreatedAt)
+		if current == nil || current.label != label {
+			if current != nil {
+				groups = append(groups, *current)
+			}
+			current = &dateGroup{label: label}
+		}
+		current.entities = append(current.entities, e)
+	}
+	if current != nil {
+		groups = append(groups, *current)
+	}
+	return groups
+}
+
+func formatDateLabel(t time.Time) string {
+	return strings.ToLower(t.Format("Jan 2"))
+}
+
+func printEntity(e *db.Entity) {
+	glyph := display.DisplayGlyph(e.Glyph, e.CardType)
+	shortID := display.FormatID(e.ID)
+
+	var line strings.Builder
+	fmt.Fprintf(&line, "%s  %-40s", glyph, e.Body)
+
+	if e.TimeAnchor != nil {
+		fmt.Fprintf(&line, " @%-5s", *e.TimeAnchor)
+	} else {
+		line.WriteString("        ")
+	}
+
+	var tagStr string
+	for _, tag := range e.Tags {
+		tagStr += " #" + tag
+	}
+	if tagStr != "" {
+		fmt.Fprintf(&line, " %-16s", strings.TrimSpace(tagStr))
+	} else {
+		line.WriteString("                 ")
+	}
+
+	fmt.Fprintf(&line, " %s", shortID)
+
+	if e.UseCount > 0 {
+		fmt.Fprintf(&line, "  (%d×)", e.UseCount)
+	}
+
+	fmt.Println(line.String())
+}