fix(web): stop season-tile flooding in channel builder and collections (#180)

Part of the #180 library picker fixes (SPA side).

Channel builder: TelevisionSeason is removed from the library grid fan-out, so a
multi-season show renders as one tile instead of one tile per season. Show tiles
gain a "Seasons" drill-in affordance (both grid and compact layouts) that opens a
dialog listing that show's seasons (via the new GET /api/library/browse?parentId=
&mediaType=TelevisionSeason), each with title, artwork and an Add button that
drops the specific season into the lineup.

Collections add-items dialog: the default search fan-out now excludes seasons,
and a media-kind filter row (All / Movies / Shows / Seasons / Artists,
default = All-without-seasons) keeps seasons reachable when explicitly selected.

Client: getLibraryBrowseItems gains an optional parentId param. Tests cover the
param mapping, the builder no longer requesting TelevisionSeason, and the
collections dialog default-excluding vs explicitly-including seasons.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/src/shell.css

@@ -2432,6 +2432,57 @@
   animation: ctv-pop 260ms cubic-bezier(0.16, 1, 0.3, 1);
 }
 
+/* Seasons drill-in affordance on show tiles (issue #180) */
+.ctv-builder-seasons-btn {
+  position: absolute;
+  left: 6px;
+  bottom: 6px;
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  padding: 3px 8px;
+  border-radius: var(--radius-sm);
+  border: 1px solid var(--border-hairline);
+  background: color-mix(in srgb, var(--surface-card) 82%, transparent);
+  color: var(--text-primary);
+  font: var(--weight-medium) var(--text-2xs) / 1 var(--font-sans);
+  cursor: pointer;
+  backdrop-filter: blur(2px);
+}
+
+.ctv-builder-seasons-btn:hover {
+  border-color: color-mix(in srgb, var(--action-primary) 45%, transparent);
+  color: var(--action-primary);
+}
+
+.ctv-builder-seasons-list {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  max-height: 420px;
+  overflow-y: auto;
+}
+
+.ctv-builder-seasons-row {
+  display: flex;
+  align-items: center;
+  gap: var(--space-5, 10px);
+  padding: 6px 8px;
+  border-radius: var(--radius-sm);
+  background: var(--surface-card);
+  border: 1px solid var(--border-hairline);
+}
+
+.ctv-builder-seasons-row-title {
+  flex: 1;
+  min-width: 0;
+  font: var(--weight-medium) var(--text-xs) / 1.15 var(--font-sans);
+  color: var(--text-primary);
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 @keyframes ctv-pop {
   from {
     transform: scale(0.2);
@@ -3658,6 +3709,35 @@
   color: var(--text-disabled);
 }
 
+/* Media-kind filter chips in the add-items dialog (issue #180) */
+.ctv-collections-picker-filters {
+  margin-top: 10px;
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+}
+
+.ctv-collections-picker-filter {
+  padding: 4px 12px;
+  border-radius: var(--radius-pill, 999px);
+  border: 1px solid var(--border-hairline);
+  background: var(--surface-card);
+  color: var(--text-secondary);
+  font: var(--weight-medium) var(--text-2xs) / 1 var(--font-sans);
+  cursor: pointer;
+}
+
+.ctv-collections-picker-filter:hover {
+  color: var(--text-primary);
+  border-color: color-mix(in srgb, var(--action-primary) 35%, transparent);
+}
+
+.ctv-collections-picker-filter-active {
+  background: color-mix(in srgb, var(--action-primary) 14%, transparent);
+  border-color: color-mix(in srgb, var(--action-primary) 45%, transparent);
+  color: var(--action-primary);
+}
+
 .ctv-collections-picker-results {
   margin-top: 10px;
   display: flex;