Import march-2020-03-10 from private repo (scrubbed 2026-05-27)

Targets Rec Room 2020.03.10 client (also serves 2020.03.06).

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 dorknet-clientpatch-{key}.zip
  for v1-march-* Release uploads.
- .github/workflows/release.yml — on tag push publishes both
  dorknet-server-march_2020_03_10-win-x64.zip and
  dorknet-clientpatch-march_2020_03_10.zip as Release assets.

Same scrub rules as december; tools/build-patcher-zip.ps1 added to
the maintainer-side allow-list so it survives.

DorkNet.Server/Data/Entities/ClubEntity.cs

@@ -0,0 +1,52 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace DorkNet.Server.Data.Entities;
+
+/// <summary>
+/// A "Group" / club — wire type <c>RecNet.Group</c>
+/// (<c>Cpp2IL_CS/.../RecNet/Group.cs</c>). Field names + types match
+/// the client's <c>Group.Deserialize</c> shape so the watch round-
+/// trips cleanly. Surfaces in the watch's profile tab as the player's
+/// primary-group affiliation.
+/// </summary>
+public class ClubEntity
+{
+    /// <summary>Mirrors wire field <c>GroupId</c>.</summary>
+    public long Id { get; set; }
+
+    [MaxLength(128)]
+    public string Name { get; set; } = string.Empty;
+
+    [MaxLength(2000)]
+    public string Description { get; set; } = string.Empty;
+
+    /// <summary>Mirrors wire <c>CreatorId</c> (Int32). Cast to int
+    /// in serialiser.</summary>
+    public long CreatorPlayerId { get; set; }
+
+    [MaxLength(256)]
+    public string ImageName { get; set; } = string.Empty;
+
+    /// <summary>GroupBanStatus enum: 0=GoodStanding, 1=InReview,
+    /// 2=TempLock, 3=Permaban.</summary>
+    public int BanStatus { get; set; } = 0;
+
+    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+    public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
+}
+
+/// <summary>One row per (club, player). Permissions is the
+/// <c>GroupMembershipPermissions</c> flags enum (Member=0, Moderator=24,
+/// CoOwner=124, Owner=127, Pending=128 for join-requests on private
+/// groups).</summary>
+public class ClubMembershipEntity
+{
+    public long Id { get; set; }
+    public long ClubId { get; set; }
+    public long PlayerId { get; set; }
+
+    /// <summary>GroupMembershipPermissions flags enum value.</summary>
+    public int Permissions { get; set; } = 0;
+
+    public DateTime JoinedAt { get; set; } = DateTime.UtcNow;
+}