docs(quick-4): complete 'Set as Default Playlist' context menu plan

- Add 4-SUMMARY.md with execution results
- Update STATE.md with quick task 004 entry

.planning/STATE.md

@@ -80,6 +80,7 @@ None currently.
 | 001 | Multi-playlist import support | 2026-02-28 | 50c8a33 | [001-multi-playlist-import-support](./quick/001-multi-playlist-import-support/) |
 | 002 | Auto-rename duplicate playlists on import | 2026-02-28 | 8ba8bbe | [002-auto-rename-duplicate-playlists-on-import](./quick/002-auto-rename-duplicate-playlists-on-import/) |
 | 003 | Add multi-select to playlist view with context menu delete support | 2026-02-28 | c92ced2 | [3-add-multi-select-to-playlist-view-with-c](./quick/3-add-multi-select-to-playlist-view-with-c/) |
+| 004 | Add "Set as Default Playlist" context menu option | 2026-02-28 | 9971b63 | [4-add-set-as-default-playlist-context-menu](./quick/4-add-set-as-default-playlist-context-menu/) |
 
 ## Session Continuity
 
@@ -99,5 +100,5 @@ None currently.
 
 ---
 *State initialized: 2026-02-27*
-Last activity: 2026-02-28 - Completed quick task 003: Add multi-select to playlist view with context menu delete support
+Last activity: 2026-02-28 - Completed quick task 004: Add "Set as Default Playlist" context menu option
 *Last updated: 2026-02-28*

.planning/quick/4-add-set-as-default-playlist-context-menu/4-SUMMARY.md

@@ -0,0 +1,59 @@
+---
+phase: quick
+plan: 4
+subsystem: frontend
+tags: [context-menu, playlist, favorites, UX]
+dependency_graph:
+  requires: [favorites-controller, playlist-view]
+  provides: [set-default-playlist-context-action]
+  affects: [playlist-view]
+tech_stack:
+  added: []
+  patterns: [context-menu-action, favCtrl-integration]
+key_files:
+  modified:
+    - frontend/src/components/playlist-view/playlist-view.ts
+decisions: []
+metrics:
+  duration: "39s"
+  completed: "2026-02-28T19:25:39Z"
+  tasks_completed: 1
+  tasks_total: 1
+---
+
+# Quick Task 4: Add "Set as Default Playlist" Context Menu Option Summary
+
+**One-liner:** Right-click context menu option to set any single playlist as the default/favorites playlist via `favCtrl.setDefaultPlaylist()`
+
+## What Was Done
+
+### Task 1: Add "Set as Default Playlist" context menu item and handler
+**Commit:** `9971b63`
+
+Two changes to `playlist-view.ts`:
+
+1. **Handler case** — Added `'set-default'` case in `onPlaylistContextAction()` switch statement, between `'rename'` and `'delete'`. Calls `this.favCtrl.setDefaultPlaylist(entry.summary.ID)` with error handling matching the pattern from `config-page.ts`.
+
+2. **Menu item** — Added `<wa-dropdown-item>` with star icon inside the existing `selectedPlaylists.size <= 1` guard block, after the Rename item. This ensures the option only appears when right-clicking a single playlist, not during multi-select.
+
+## Verification
+
+- ✅ TypeScript compilation passes (`npx tsc --noEmit` — zero errors)
+- ✅ Pre-commit hook (frontend-typecheck) passes
+- ✅ Menu item is inside single-select guard — hidden during multi-select
+- ✅ Handler calls `favCtrl.setDefaultPlaylist()` with correct playlist ID
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+## Commits
+
+| # | Hash | Message |
+|---|------|---------|
+| 1 | `9971b63` | feat(quick-4): add 'Set as Default Playlist' context menu option |
+
+## Self-Check: PASSED
+
+- ✅ `frontend/src/components/playlist-view/playlist-view.ts` exists
+- ✅ Commit `9971b63` exists in git log