Client JWT authentication (#723)

## Description:

Send JWT to the game server for verification.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [ ] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>

src/server/jwt.ts

@@ -0,0 +1,29 @@
+import { jwtVerify } from "jose";
+import { TokenPayload, TokenPayloadSchema } from "../core/ApiSchemas";
+import { ServerConfig } from "../core/configuration/Config";
+
+type TokenVerificationResult = {
+  persistentId: string;
+  claims: TokenPayload | null;
+};
+
+export async function verifyClientToken(
+  token: string,
+  config: ServerConfig,
+): Promise<TokenVerificationResult> {
+  if (token.length === 36) {
+    return { persistentId: token, claims: null };
+  }
+  const issuer = config.jwtIssuer();
+  const audience = config.jwtAudience();
+  const key = await config.jwkPublicKey();
+  const { payload, protectedHeader } = await jwtVerify(token, key, {
+    algorithms: ["EdDSA"],
+    issuer,
+    audience,
+    maxTokenAge: "6 days",
+  });
+  const claims = TokenPayloadSchema.parse(payload);
+  const persistentId = claims.sub;
+  return { persistentId, claims };
+}