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/commands.go

@@ -8,6 +8,7 @@ import (
 	"github.com/atotto/clipboard"
 	tea "github.com/charmbracelet/bubbletea"
 
+	"github.com/lerko/nib/internal/carddata"
 	"github.com/lerko/nib/internal/db"
 )
 
@@ -29,7 +30,8 @@ type entityUpdatedMsg struct {
 }
 
 type entityPromotedMsg struct {
-	id string
+	id       string
+	cardType db.CardType
 }
 
 type entityDemotedMsg struct {
@@ -122,12 +124,13 @@ func pinEntity(store *db.Store, e *db.Entity) tea.Cmd {
 	}
 }
 
-func promoteEntity(store *db.Store, id string) tea.Cmd {
+func promoteEntity(store *db.Store, id string, ct db.CardType, body string) tea.Cmd {
 	return func() tea.Msg {
-		if err := store.Promote(id, db.CardSnippet, nil); err != nil {
+		cd := carddata.GenerateCardData(ct, body)
+		if err := store.Promote(id, ct, cd); err != nil {
 			return errMsg{err}
 		}
-		return entityPromotedMsg{id}
+		return entityPromotedMsg{id, ct}
 	}
 }