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/ObjectiveProgressEntity.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace DorkNet.Server.Data.Entities;
+
+/// <summary>
+/// Per-player objective / achievement progress. The 2020 client's
+/// <c>Objectives.MyProgress</c> response is two arrays — Objectives
+/// and ObjectiveGroups — keyed by string id. We collapse that to one
+/// table here; group rows distinguish themselves with a leading
+/// <c>group:</c> prefix on <see cref="Key"/>.
+/// </summary>
+public class ObjectiveProgressEntity
+{
+    public long Id { get; set; }
+    public long PlayerId { get; set; }
+
+    /// <summary>Objective id from the client's hardcoded objective
+    /// table (e.g. <c>tutorial_dorm_decorate</c>). Group rows use
+    /// <c>group:&lt;groupId&gt;</c>.</summary>
+    [MaxLength(128)]
+    public string Key { get; set; } = string.Empty;
+
+    public bool IsCompleted { get; set; }
+    public DateTime? ClearedAt { get; set; }
+}