feat(tui): add broot-style tab affordances to header and footer

Header now renders stream/cards as tabs with keybindings inline —
active tab highlighted, inactive shows the key to switch. Footer
shows a capture tab affordance when in list state. Redundant mode
and capture hints removed from the context hint bar.

internal/tui/model.go

@@ -786,16 +786,13 @@ func (m model) listContent() string {
 }
 
 func (m model) headerView() string {
-	header := titleStyle.Render("nib")
-
-	modeName := "stream"
-	if m.mode == modeCards {
-		modeName = "cards"
-	}
-	header += " " + modeStyle.Render(modeName)
+	header := titleStyle.Render("nib") + "  "
+	header += renderTab("stream", "1", m.mode == modeStream)
+	header += " " + separatorStyle.Render("│") + " "
+	header += renderTab("cards", "2", m.mode == modeCards)
 
 	if m.filterTag != "" {
-		header += " " + filterPillStyle.Render("#"+m.filterTag)
+		header += "  " + filterPillStyle.Render("#"+m.filterTag)
 	}
 
 	if m.hasSearch() {

internal/tui/statusbar.go

@@ -20,14 +20,28 @@ func renderHints(hints []hint) string {
 	return strings.Join(parts, "  ")
 }
 
-func renderStatusBar(m model, width int) string {
-	left := countText(m)
-	if m.status != "" {
-		left = m.status
+func renderTab(label, key string, active bool) string {
+	if active {
+		return hintKeyStyle.Render(label) + " " + hintDescStyle.Render(key)
 	}
-	right := renderHints(contextHints(m))
+	return hintDescStyle.Render(label) + " " + hintKeyStyle.Render(key)
+}
 
-	leftRendered := statusStyle.Render(left)
+func renderStatusBar(m model, width int) string {
+	var leftParts []string
+
+	if m.state == stateList {
+		leftParts = append(leftParts, renderTab("capture", "a", false))
+	}
+
+	if m.status != "" {
+		leftParts = append(leftParts, statusStyle.Render(m.status))
+	} else {
+		leftParts = append(leftParts, statusStyle.Render(countText(m)))
+	}
+
+	leftRendered := strings.Join(leftParts, " "+separatorStyle.Render("│")+" ")
+	right := renderHints(contextHints(m))
 
 	gap := width - lipgloss.Width(leftRendered) - lipgloss.Width(right)
 	if gap < 0 {
@@ -77,11 +91,11 @@ func contextHints(m model) []hint {
 			if m.focus == focusDetail {
 				return []hint{{"h", "list"}, {"c", "copy"}, {"e", "edit"}, {"p", "promote"}, {"D", "demote"}, {"!", "pin"}, {"esc", "back"}}
 			}
-			return []hint{{"l", "detail"}, {"a", "add"}, {"d", "del"}, {"#", "filter"}, {"esc", "close"}, {"?", "help"}, {"q", "quit"}}
+			return []hint{{"l", "detail"}, {"d", "del"}, {"#", "filter"}, {"esc", "close"}, {"?", "help"}, {"q", "quit"}}
 		}
 		if m.mode == modeCards {
-			return []hint{{"1", "stream"}, {"2", "cards"}, {"s", "sort"}, {"tab", "intent"}, {"a", "add"}, {"?", "help"}, {"q", "quit"}}
+			return []hint{{"s", "sort"}, {"tab", "intent"}, {"?", "help"}, {"q", "quit"}}
 		}
-		return []hint{{"1", "stream"}, {"2", "cards"}, {"a", "add"}, {"?", "search"}, {"m", "absorb"}, {"d", "del"}, {"#", "filter"}, {"?", "help"}, {"q", "quit"}}
+		return []hint{{"?", "search"}, {"m", "absorb"}, {"d", "del"}, {"#", "filter"}, {"?", "help"}, {"q", "quit"}}
 	}
 }