feat(db): add session-vector capture queries; LikeTrack returns row count

ListRecentSessionTracks + UpdatePlayEventVector for the vector capture
path inside RecordPlayStarted. LikeTrack switches to :execrows so the
contextual-likes capture can detect insert vs already-exists. Existing
callers updated to ignore the count for now; later tasks consume it.

internal/subsonic/star.go

@@ -38,7 +38,7 @@ func (m *mediaHandlers) handleStar(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if trackID.Valid {
-		if err := q.LikeTrack(r.Context(), dbq.LikeTrackParams{UserID: user.ID, TrackID: trackID}); err != nil {
+		if _, err := q.LikeTrack(r.Context(), dbq.LikeTrackParams{UserID: user.ID, TrackID: trackID}); err != nil {
 			WriteFail(w, r, ErrGeneric, "Could not star track")
 			return
 		}

internal/subsonic/star_test.go

@@ -198,7 +198,7 @@ func TestHandleGetStarred2_ReturnsAllThreeArrays(t *testing.T) {
 	q := dbq.New(pool)
 
 	// Star one of each.
-	_ = q.LikeTrack(context.Background(), dbq.LikeTrackParams{UserID: user.ID, TrackID: track.ID})
+	_, _ = q.LikeTrack(context.Background(), dbq.LikeTrackParams{UserID: user.ID, TrackID: track.ID})
 	_ = q.LikeAlbum(context.Background(), dbq.LikeAlbumParams{UserID: user.ID, AlbumID: album.ID})
 	_ = q.LikeArtist(context.Background(), dbq.LikeArtistParams{UserID: user.ID, ArtistID: artist.ID})
 
@@ -232,7 +232,7 @@ func TestHandleGetStarred2_CrossUserIsolation(t *testing.T) {
 	bob, _ := q.CreateUser(context.Background(), dbq.CreateUserParams{
 		Username: "bob", PasswordHash: "x", ApiToken: "y", IsAdmin: false,
 	})
-	_ = q.LikeTrack(context.Background(), dbq.LikeTrackParams{UserID: alice.ID, TrackID: track.ID})
+	_, _ = q.LikeTrack(context.Background(), dbq.LikeTrackParams{UserID: alice.ID, TrackID: track.ID})
 
 	m := newStarHandlers(pool)
 	req := httptest.NewRequest(http.MethodGet, "/rest/getStarred2?f=json", nil)