Import december-2020-12-18 from private repo (scrubbed 2026-05-27)

Targets Rec Room 2020.12.18 client.

Re-import after adding:
- DorkNet.ClientMod/dorknet-clientmod.json.template — config schema
  the launcher's manifest-driven patcher renders into UserData/.
- tools/build-patcher-zip.ps1 — produces the dorknet-clientpatch-{key}.zip
  Release asset the launcher fetches.
- .github/workflows/release.yml — auto-publishes both Release assets
  on v1-december-* tag push.

Scrubbed via maintainer-side scrub-for-public.ps1: same drop rules as
the prior import, plus build-patcher-zip.ps1 added to the tools/
allow-list so it survives the scrub.

DorkNet.Server/Data/Entities/PlaylistInteractionEntity.cs

@@ -0,0 +1,24 @@
+namespace DorkNet.Server.Data.Entities;
+
+/// <summary>
+/// One row per (PlaylistId, PlayerId) tracking the player's cheer
+/// + favorite flags on a playlist. Drives <c>/playlists/{id}/interactionby/me</c>
+/// (read), the four interactionby/me mutation endpoints (cheer /
+/// uncheer / favorite / unfavorite toggles), and the
+/// <c>playlists/cheeredby/me</c> + <c>playlists/favoritedby/me</c>
+/// lists.
+///
+/// Counter columns on <see cref="PlaylistEntity"/> (CheerCount /
+/// FavoriteCount) are kept in sync by <see cref="DorkNet.Server.Services.PlaylistService"/>
+/// on each toggle so the hot ranking + tile badges read from the
+/// row without an aggregate join.
+/// </summary>
+public class PlaylistInteractionEntity
+{
+    public long Id { get; set; }
+    public long PlaylistId { get; set; }
+    public long PlayerId { get; set; }
+    public bool Cheered { get; set; } = false;
+    public bool Favorited { get; set; } = false;
+    public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
+}