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/Controllers/API/PlayerElo/PlayerEloController.cs

@@ -0,0 +1,69 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using DorkNet.Server.Auth;
+using DorkNet.Server.Data;
+using DorkNet.Server.Data.Entities;
+
+namespace DorkNet.Server.Controllers.API.PlayerElo;
+
+/// <summary>
+/// api.rec.net/api/PlayerElo/* — match-result Elo deltas. The 2020
+/// client posts after each ranked match (Royale, Paintball, Soccer)
+/// with a delta the server applies to the per-player Elo row.
+///
+/// Wire request matches <c>RecNet.Elo.ReportPlayerElo</c>:
+///   <c>{GameMode(int), EloDelta(int), Won(bool)}</c>
+/// (we tolerate a few synonym fields). Response: the new Elo as a
+/// JSON primitive int.
+/// </summary>
+[ApiController]
+public class PlayerEloController(DorkNetDbContext db) : ControllerBase
+{
+    private long Me => this.RequireCurrentPlayerId();
+
+    public sealed class ReportEloRequest
+    {
+        public int GameMode { get; set; }
+        public int EloDelta { get; set; }
+        public bool Won { get; set; }
+    }
+
+    [HttpPost("api/PlayerElo/v1/reportPlayerElo")]
+    [Authorize]
+    public async Task<IActionResult> ReportPlayerElo([FromBody] ReportEloRequest req)
+    {
+        var pid = Me;
+        var row = await db.PlayerElo.FirstOrDefaultAsync(p =>
+            p.PlayerId == pid && p.GameMode == req.GameMode);
+        if (row is null)
+        {
+            row = new PlayerEloEntity
+            {
+                PlayerId = pid,
+                GameMode = req.GameMode,
+            };
+            db.PlayerElo.Add(row);
+        }
+        // Clamp Elo to a reasonable range to avoid overflow exploits.
+        row.Elo = Math.Clamp(row.Elo + req.EloDelta, 0, 5000);
+        row.MatchesPlayed += 1;
+        if (req.Won) row.Wins += 1; else row.Losses += 1;
+        row.UpdatedAt = DateTime.UtcNow;
+        await db.SaveChangesAsync();
+        return Ok(row.Elo);
+    }
+
+    [HttpGet("api/PlayerElo/v1/get")]
+    public async Task<IActionResult> Get(
+        [FromQuery] long? playerId, [FromQuery] int gameMode = 0)
+    {
+        var pid = playerId ?? this.CurrentPlayerId() ?? 0;
+        if (pid == 0) return Ok(new { Elo = 1000, Wins = 0, Losses = 0 });
+        var row = await db.PlayerElo.FirstOrDefaultAsync(p =>
+            p.PlayerId == pid && p.GameMode == gameMode);
+        return Ok(row is null
+            ? new { Elo = 1000, Wins = 0, Losses = 0 }
+            : new { row.Elo, row.Wins, row.Losses });
+    }
+}