feat: Add support for 2018 client API endpoints and data models

- Implemented new search endpoints for rooms to accommodate the 2018 client.
- Added support for retrieving room details and featured rooms in a format compatible with the 2018 client.
- Introduced new data models for login responses and player presence specific to the 2018 client.
- Created mappers to convert between internal entities and the 2018 wire formats for players and rooms.
- Updated existing storefront APIs to include versioned endpoints for the 2018 client.
- Enhanced the version controller to return dual-format responses for compatibility with both 2018 and 2020 clients.
- Refactored the configuration service to ensure trailing slashes in URLs for the 2018 client.

DorkNet.Server/Controllers/API/Presence/PresenceController.cs

@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using DorkNet.Models.Players;
+using DorkNet.Server.Services;
+
+namespace DorkNet.Server.Controllers.API.Presence;
+
+/// <summary>
+/// api/presence/* — the June-2018 client's friend-presence poll (every ~30s,
+/// RecNet.cs:63249). POST api/presence/v2/list takes a JSON array of account
+/// ids and returns one <see cref="Presence2018"/> per id. There is no 2020
+/// equivalent on this host (the 2020 client used match.rec.net/player), so this
+/// controller is 2018-specific. Online state comes from
+/// <see cref="OnlinePresenceService"/>; GameSession is left null for now (the
+/// client renders "online" without it and fills in room info on join).
+/// </summary>
+[ApiController]
+[Authorize]
+public class PresenceController(OnlinePresenceService presence) : ControllerBase
+{
+    [HttpPost("/api/presence/v2/list")]
+    [HttpPost("/api/presence/v1/list")]
+    public ActionResult<List<Presence2018>> List([FromBody] long[]? ids)
+    {
+        if (ids is null || ids.Length == 0) return Ok(new List<Presence2018>());
+        var online = presence.OnlinePlayerIds().ToHashSet();
+        var result = ids.Distinct().Select(id => new Presence2018
+        {
+            PlayerId = id,
+            IsOnline = online.Contains(id),
+            GameSession = null,
+        }).ToList();
+        return Ok(result);
+    }
+}