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/Infrastructure/NoWireEncryptionAttribute.cs

@@ -0,0 +1,12 @@
+namespace SVSim.EmulatedEntrypoint.Infrastructure;
+
+/// <summary>
+/// Applied to a controller or action that speaks the same msgpack + standard envelope as the
+/// rest of the game API but WITHOUT the AES wrapper. Used for endpoints hosted on
+/// <c>shadowverse-portal.com</c> (deck builder, deck image), which use plaintext msgpack on the
+/// wire — see <c>docs/api-spec/endpoints/deck-builder/*.md</c>. The translation middleware
+/// detects the attribute and skips <c>Encryption.Decrypt</c> / <c>Encryption.Encrypt</c>; the
+/// base64 wrap on the response and the msgpack ↔ JSON pivot stay the same.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true)]
+public sealed class NoWireEncryptionAttribute : Attribute { }