Save source descriptions, add "Why it's #N", fix IGDB studio names

Descriptions
- Items keep the source's description (TMDB/TheTVDB overview, IGDB
  summary, Wikipedia intro) in a new items.description column
  (migration 3); editable in the item form
- Deezer/MusicBrainz track counts and album names are now display-only
  hints, not saved as descriptions

Why it's #N
- The owner's note is presented as "Why it's #N" in the editor and the
  public detail view, above an "About" section with the description

IGDB developers
- IGDB credits internal divisions ("Nintendo EAD", "Nintendo EPD
  Production Group No. 8"). A developer whose name shares its first word
  with its parent company is credited to the parent ("Nintendo");
  independently named studios keep their name (Retro Studios, Naughty
  Dog, Landfall Games)
- Fall back to the publisher when IGDB lists no developer

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/store/items.go

@@ -20,17 +20,18 @@ type Item struct {
 	Provider    string            `json:"provider"`
 	ProviderID  string            `json:"providerId"`
 	ExternalURL string            `json:"externalUrl"`
-	Note        string            `json:"note"`
+	Description string            `json:"description"` // from the source, editable
+	Note        string            `json:"note"`        // the owner's "why it's here"
 	Extra       map[string]string `json:"extra"`
 }
 
-const itemColumns = `id, list_id, rank, title, subtitle, year, image, image_source, provider, provider_id, external_url, note, extra`
+const itemColumns = `id, list_id, rank, title, subtitle, year, image, image_source, provider, provider_id, external_url, description, note, extra`
 
 func scanItem(row interface{ Scan(...any) error }) (Item, error) {
 	var it Item
 	var extra string
 	err := row.Scan(&it.ID, &it.ListID, &it.Rank, &it.Title, &it.Subtitle, &it.Year, &it.Image, &it.ImageSource,
-		&it.Provider, &it.ProviderID, &it.ExternalURL, &it.Note, &extra)
+		&it.Provider, &it.ProviderID, &it.ExternalURL, &it.Description, &it.Note, &extra)
 	if errors.Is(err, sql.ErrNoRows) {
 		return it, ErrNotFound
 	}
@@ -82,11 +83,12 @@ func (it *Item) normalize() error {
 	it.Subtitle = strings.TrimSpace(it.Subtitle)
 	it.Year = strings.TrimSpace(it.Year)
 	it.Note = strings.TrimSpace(it.Note)
+	it.Description = strings.TrimSpace(it.Description)
 	it.ExternalURL = strings.TrimSpace(it.ExternalURL)
 	if it.Title == "" {
 		return invalid("Title is required")
 	}
-	if len(it.Title) > 500 || len(it.Subtitle) > 500 || len(it.Year) > 20 || len(it.Note) > 10000 || len(it.ExternalURL) > 2000 {
+	if len(it.Title) > 500 || len(it.Subtitle) > 500 || len(it.Year) > 20 || len(it.Note) > 10000 || len(it.Description) > 10000 || len(it.ExternalURL) > 2000 {
 		return invalid("One of the fields is too long")
 	}
 	if it.ExternalURL != "" && !strings.HasPrefix(it.ExternalURL, "https://") && !strings.HasPrefix(it.ExternalURL, "http://") {
@@ -136,9 +138,9 @@ func (s *Store) AddItem(ctx context.Context, it Item, rank int) (Item, error) {
 	if _, err := tx.ExecContext(ctx, `UPDATE items SET rank = rank + 1 WHERE list_id = ? AND rank >= ?`, it.ListID, rank); err != nil {
 		return it, err
 	}
-	res, err := tx.ExecContext(ctx, `INSERT INTO items (list_id, rank, title, subtitle, year, image, image_source, provider, provider_id, external_url, note, extra)
-		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
-		it.ListID, rank, it.Title, it.Subtitle, it.Year, it.Image, it.ImageSource, it.Provider, it.ProviderID, it.ExternalURL, it.Note, extraJSON(it.Extra))
+	res, err := tx.ExecContext(ctx, `INSERT INTO items (list_id, rank, title, subtitle, year, image, image_source, provider, provider_id, external_url, description, note, extra)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		it.ListID, rank, it.Title, it.Subtitle, it.Year, it.Image, it.ImageSource, it.Provider, it.ProviderID, it.ExternalURL, it.Description, it.Note, extraJSON(it.Extra))
 	if err != nil {
 		return it, err
 	}
@@ -157,8 +159,8 @@ func (s *Store) UpdateItem(ctx context.Context, it Item) (Item, error) {
 	if err := it.normalize(); err != nil {
 		return it, err
 	}
-	res, err := s.db.ExecContext(ctx, `UPDATE items SET title=?, subtitle=?, year=?, image=?, image_source=?, external_url=?, note=?, extra=?, updated_at=unixepoch() WHERE id=?`,
-		it.Title, it.Subtitle, it.Year, it.Image, it.ImageSource, it.ExternalURL, it.Note, extraJSON(it.Extra), it.ID)
+	res, err := s.db.ExecContext(ctx, `UPDATE items SET title=?, subtitle=?, year=?, image=?, image_source=?, external_url=?, description=?, note=?, extra=?, updated_at=unixepoch() WHERE id=?`,
+		it.Title, it.Subtitle, it.Year, it.Image, it.ImageSource, it.ExternalURL, it.Description, it.Note, extraJSON(it.Extra), it.ID)
 	if err != nil {
 		return it, err
 	}