feat(tui): add split-pane detail, compact date headers, and input drawer

Three layout improvements for better space utilization:

- Compact date headers: date labels render as left gutter column instead
  of standalone lines, saving one line per date group in stream view
- Input drawer: capture bar expands to 4-line drawer with border, hints,
  and live preview of parsed entity/search query
- Split-pane detail: wide terminals (>=100 cols) show list and detail
  side-by-side with h/l focus switching, falling back to full-screen
  detail on narrow terminals

internal/tui/list.go

@@ -93,6 +93,8 @@ func (l listModel) update(msg tea.KeyMsg) listModel {
 	return l
 }
 
+const dateGutterWidth = 9
+
 func (l listModel) view(width int) string {
 	ents := l.displayEntities()
 	if len(ents) == 0 {
@@ -100,22 +102,24 @@ func (l listModel) view(width int) string {
 	}
 
 	groups := groupByDate(ents)
+	entityWidth := width - 4 - dateGutterWidth
 
 	type displayLine struct {
 		text      string
 		entityIdx int
-		isHeader  bool
 	}
 
 	var lines []displayLine
 	entityIdx := 0
 	for _, g := range groups {
-		lines = append(lines, displayLine{
-			text:     dateHeaderStyle.Render("── " + g.label + " ──"),
-			isHeader: true,
-		})
-		for _, e := range g.entities {
-			line := renderEntity(e, width-4)
+		for i, e := range g.entities {
+			var gutter string
+			if i == 0 {
+				gutter = gutterStyle.Render(padRight(g.label, 6) + " │ ")
+			} else {
+				gutter = gutterStyle.Render("       │ ")
+			}
+			line := gutter + renderEntity(e, entityWidth)
 			lines = append(lines, displayLine{
 				text:      line,
 				entityIdx: entityIdx,
@@ -124,21 +128,17 @@ func (l listModel) view(width int) string {
 		}
 	}
 
-	cursorLine := l.cursorDisplayLine(groups)
 	visible := l.visibleCount()
-
 	offset := 0
-	if cursorLine >= visible {
-		offset = cursorLine - visible + 1
+	if l.cursor >= visible {
+		offset = l.cursor - visible + 1
 	}
 
 	var b strings.Builder
 	end := min(offset+visible, len(lines))
 	for i := offset; i < end; i++ {
 		dl := lines[i]
-		if dl.isHeader {
-			b.WriteString(dl.text)
-		} else if dl.entityIdx == l.cursor {
+		if dl.entityIdx == l.cursor {
 			b.WriteString(selectedItemStyle.Render(" " + dl.text))
 		} else {
 			b.WriteString(listItemStyle.Render(dl.text))
@@ -151,22 +151,6 @@ func (l listModel) view(width int) string {
 	return b.String()
 }
 
-func (l listModel) cursorDisplayLine(groups []dateGroup) int {
-	line := 0
-	entityIdx := 0
-	for _, g := range groups {
-		line++
-		for range g.entities {
-			if entityIdx == l.cursor {
-				return line
-			}
-			line++
-			entityIdx++
-		}
-	}
-	return 0
-}
-
 func (l listModel) visibleCount() int {
 	if l.height <= 0 {
 		return 20
@@ -203,6 +187,14 @@ func formatDateLabel(t time.Time) string {
 	return strings.ToLower(t.Format("Jan 2"))
 }
 
+func padRight(s string, n int) string {
+	r := []rune(s)
+	if len(r) >= n {
+		return string(r[:n])
+	}
+	return s + strings.Repeat(" ", n-len(r))
+}
+
 func renderEntity(e *db.Entity, maxWidth int) string {
 	glyphStr := display.DisplayGlyph(e.Glyph, e.CardType)
 	style := glyphStyle