feat(deck-builder): /deck_code mint + /deck resolve with 3-min in-memory TTL

Adds the portal pair (shadowverse-portal.com deck-builder endpoints) as
anonymous routes on the app server. The translation middleware learns a new
[NoWireEncryption] attribute that skips both AES calls but keeps the rest of
the msgpack + base64 + envelope pipeline intact, matching prod's portal wire
profile observed in data_dumps/traffic_prod_deckcode.ndjson.

Storage is a 3-minute IMemoryCache — codes are anonymous-global, 4-char
lowercase alphanumeric (matches the shortest prod sample). Foil bit is
stripped on mint to match prod's normalize-on-encode behaviour.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Models/Dtos/Common/PortalErrors.cs

@@ -0,0 +1,22 @@
+using MessagePack;
+using System.Text.Json.Serialization;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.Common;
+
+/// <summary>
+/// The portal (shadowverse-portal.com) wraps every response with an `errors` object that is
+/// present even on success — the success-path payload carries a stub `UNKNOWN_ERROR` / "error
+/// message" pair that the client ignores when result_code == 1. See
+/// <c>docs/api-spec/endpoints/deck-builder/*.md</c>.
+/// </summary>
+[MessagePackObject]
+public class PortalErrors
+{
+    [JsonPropertyName("type")]
+    [Key("type")]
+    public string Type { get; set; } = "UNKNOWN_ERROR";
+
+    [JsonPropertyName("message")]
+    [Key("message")]
+    public string Message { get; set; } = "";
+}