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.Models/Players/Progression.cs

@@ -0,0 +1,26 @@
+using System.Text.Json.Serialization;
+
+namespace DorkNet.Models.Players;
+
+/// <summary>
+/// RecNet.Progression — dump.cs:582273, Deserialize at RVA 0x1142BB0.
+///
+/// Verified by disassembly: reads "PlayerId", "Level", "XP" via
+/// Util.GetKey&lt;int&gt;. All three keys are required (non-default) — missing
+/// any of them throws KeyNotFoundException at the client.
+///
+/// Note: the JSON uses "PlayerId" not "AccountId" even though the C# property
+/// is AccountId on most other types. Returned by:
+///   GET api.rec.net/api/players/v1/progression/{accountId}
+/// </summary>
+public class Progression
+{
+    [JsonPropertyName("PlayerId")]
+    public int PlayerId { get; set; }
+
+    [JsonPropertyName("Level")]
+    public int Level { get; set; } = 1;
+
+    [JsonPropertyName("XP")]
+    public int XP { get; set; } = 0;
+}