Blank root panel, asset form as a modal, and a dedicated Statuses page

- Main panel is now blank at the top level ("Select a folder or asset
  from the tree") instead of showing a dashboard - browsing happens in
  the tree, the panel only shows something once you click into it.
  Removed the now-dead DashboardStats/Stats() machinery it depended on.
- Add/Edit Asset no longer takes over the main panel; it opens in
  #assetModal instead; asset_form.html was trimmed down to just the form
  (no more breadcrumb/panel wrapper) since the modal chrome provides the
  title and footer buttons now. The dynamic item-type-fields and submit
  listeners moved from #main-panel's delegation to the modal element's.
- Statuses split out of the General settings page into its own
  /settings/statuses page and sub-nav entry, alongside General, Item
  Types, and Users.

internal/assets/assets.go

@@ -466,84 +466,3 @@ func (s *Store) descendantFolderIDs(ctx context.Context, rootID int64) ([]int64,
 	walk(rootID)
 	return out, nil
 }
-
-// DashboardStats summarizes inventory counts for the small dashboard.
-type DashboardStats struct {
-	Total         int
-	ByStatus      []StatusCount
-	ByType        []TypeCount
-	RecentlyAdded []models.Asset
-}
-
-type StatusCount struct {
-	Name  string
-	Color string
-	Count int
-}
-
-type TypeCount struct {
-	Name  string
-	Icon  string
-	Count int
-}
-
-func (s *Store) Stats(ctx context.Context) (*DashboardStats, error) {
-	stats := &DashboardStats{}
-	if err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM assets`).Scan(&stats.Total); err != nil {
-		return nil, err
-	}
-
-	rows, err := s.db.QueryContext(ctx, `
-		SELECT st.name, st.color, COUNT(a.id)
-		FROM statuses st LEFT JOIN assets a ON a.status_id = st.id
-		GROUP BY st.id ORDER BY st.sort_order ASC`)
-	if err != nil {
-		return nil, err
-	}
-	for rows.Next() {
-		var sc StatusCount
-		if err := rows.Scan(&sc.Name, &sc.Color, &sc.Count); err != nil {
-			rows.Close()
-			return nil, err
-		}
-		stats.ByStatus = append(stats.ByStatus, sc)
-	}
-	rows.Close()
-	if err := rows.Err(); err != nil {
-		return nil, err
-	}
-
-	rows, err = s.db.QueryContext(ctx, `
-		SELECT it.name, it.icon, COUNT(a.id)
-		FROM item_types it LEFT JOIN assets a ON a.item_type_id = it.id
-		GROUP BY it.id HAVING COUNT(a.id) > 0 ORDER BY COUNT(a.id) DESC`)
-	if err != nil {
-		return nil, err
-	}
-	for rows.Next() {
-		var tc TypeCount
-		if err := rows.Scan(&tc.Name, &tc.Icon, &tc.Count); err != nil {
-			rows.Close()
-			return nil, err
-		}
-		stats.ByType = append(stats.ByType, tc)
-	}
-	rows.Close()
-	if err := rows.Err(); err != nil {
-		return nil, err
-	}
-
-	recentRows, err := s.db.QueryContext(ctx, assetSelect+` ORDER BY a.created_at DESC LIMIT 8`)
-	if err != nil {
-		return nil, err
-	}
-	defer recentRows.Close()
-	for recentRows.Next() {
-		a, err := scanAsset(recentRows)
-		if err != nil {
-			return nil, err
-		}
-		stats.RecentlyAdded = append(stats.RecentlyAdded, *a)
-	}
-	return stats, recentRows.Err()
-}