feat(tui): add cards view, mode switching, promote picker, and card detail

Stream/cards toggle with 1/2 keys. Cards view with intent filtering
(tab cycles grab/read/fill/all), sort cycling (s key), pinned-first
ordering, and affordance badges. Promote picker (p key) with card type
selection and auto-detection from body content. Detail view renders
card_data per type: checklist steps, template slots, decision fields,
link URLs.

Extracts generateCardData to internal/carddata for reuse across cmd
and tui packages.

internal/tui/styles.go

@@ -77,4 +77,28 @@ var (
 
 	helpDescStyle = lipgloss.NewStyle().
 			Foreground(dim)
+
+	affordanceStyle = lipgloss.NewStyle().
+			Foreground(lipgloss.AdaptiveColor{Light: "#5B8EF0", Dark: "#7AAFFF"}).
+			Bold(true)
+
+	useCountStyle = lipgloss.NewStyle().
+			Foreground(lipgloss.AdaptiveColor{Light: "#B07D3A", Dark: "#D4A54A"})
+
+	modeStyle = lipgloss.NewStyle().
+			Foreground(dim).
+			Bold(true)
+
+	detailLabelStyle = lipgloss.NewStyle().
+				Foreground(highlight).
+				Bold(true)
+
+	detailValueStyle = lipgloss.NewStyle().
+				Foreground(lipgloss.AdaptiveColor{Light: "#555555", Dark: "#BBBBBB"})
+
+	checkDoneStyle = lipgloss.NewStyle().
+			Foreground(lipgloss.AdaptiveColor{Light: "#43BF6D", Dark: "#73F59F"})
+
+	checkPendingStyle = lipgloss.NewStyle().
+				Foreground(dim)
 )