refactor: collapse per-env Configs into ClientEnv + ServerEnv (#3906)

## Description:

This is a refactor to simplify config handling.

Replaces the per-environment DevConfig/PreprodConfig/ProdConfig class
hierarchy with two static classes: ClientEnv (browser main thread, reads
from window.BOOTSTRAP_CONFIG) and ServerEnv (Node server, reads from
process.env). The four config classes are deleted, the abstract
DefaultServerConfig is gone, and DefaultConfig is renamed to Config.

The values that flow server → client (gameEnv, numWorkers,
turnstileSiteKey, jwtAudience, instanceId) used to be baked into the
hardcoded per-env classes. They're now real env vars on the server,
embedded into a single window.BOOTSTRAP_CONFIG object in index.html at
request time (alongside the existing gitCommit/assetManifest/cdnBase
globals, which moved into the same object), and read back by ClientEnv
on the client. The dev defaults previously hidden inside DevServerConfig
are now explicit in start:server-dev (NUM_WORKERS=2,
TURNSTILE_SITE_KEY=1x..., JWT_AUDIENCE=localhost, etc.) and in
vite.config.ts's html plugin inject.data. Production deploys plumb
NUM_WORKERS and TURNSTILE_SITE_KEY through deploy.yml (GitHub vars) into
the remote env file; JWT_AUDIENCE is derived from DOMAIN in deploy.sh.
The dynamic /api/instance endpoint is gone — INSTANCE_ID rides along in
BOOTSTRAP_CONFIG now.

ServerEnv is the only thing server code touches; ClientEnv is
browser-only. The two classes have intentional overlap (env, numWorkers,
jwtIssuer, gameCreationRate, workerIndex, etc.) since they derive
identical logic from different sources — there's a TODO in each to
consolidate via a shared helper later. The game-logic Config no longer
stores a ServerConfig/ClientEnv reference and its serverConfig() getter
is gone; the one caller (MultiTabModal) now reads ClientEnv.env()
directly. Worker init no longer carries server-config values since
nothing in the worker actually reads them.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

tests/core/configuration/ConfigLoader.test.ts

@@ -1,44 +1,87 @@
+import { ClientEnv } from "src/client/ClientEnv";
 import { beforeEach, describe, expect, test, vi } from "vitest";
-import { GameEnv } from "../../../src/core/configuration/Config";
-import {
-  clearCachedRuntimeClientServerConfig,
-  GameLogicEnv,
-  getBuildTimeGameLogicEnv,
-  getGameLogicConfig,
-  getRuntimeClientServerConfig,
-  getServerConfigForGameLogicEnv,
-} from "../../../src/core/configuration/ConfigLoader";
+import { GameEnv, parseGameEnv } from "../../../src/core/configuration/Config";
 
-describe("ConfigLoader", () => {
-  const originalGameEnv = process.env.GAME_ENV;
+describe("parseGameEnv", () => {
+  test("maps 'dev' to GameEnv.Dev", () => {
+    expect(parseGameEnv("dev")).toBe(GameEnv.Dev);
+  });
+  test("maps 'staging' to GameEnv.Preprod", () => {
+    expect(parseGameEnv("staging")).toBe(GameEnv.Preprod);
+  });
+  test("maps 'prod' to GameEnv.Prod", () => {
+    expect(parseGameEnv("prod")).toBe(GameEnv.Prod);
+  });
+  test("throws on undefined", () => {
+    expect(() => parseGameEnv(undefined)).toThrow(/unsupported game env/);
+  });
+  test("throws on unknown value", () => {
+    expect(() => parseGameEnv("production")).toThrow(/unsupported game env/);
+  });
+});
 
+describe("ClientEnv", () => {
   beforeEach(() => {
     vi.restoreAllMocks();
     window.BOOTSTRAP_CONFIG = undefined;
-    process.env.GAME_ENV = originalGameEnv;
-    clearCachedRuntimeClientServerConfig();
+    ClientEnv.reset();
   });
 
-  test("uses runtime bootstrap config without fetching /api/env", async () => {
-    window.BOOTSTRAP_CONFIG = { gameEnv: "staging" };
+  test("reads from window.BOOTSTRAP_CONFIG without fetching", () => {
+    window.BOOTSTRAP_CONFIG = {
+      gameEnv: "staging",
+      numWorkers: 4,
+      turnstileSiteKey: "test-key",
+      jwtAudience: "openfront.dev",
+      instanceId: "TEST_ID",
+      gitCommit: "abc123",
+    };
     const fetchSpy = vi.spyOn(globalThis, "fetch");
 
-    const config = await getRuntimeClientServerConfig();
-
-    expect(config.env()).toBe(GameEnv.Preprod);
+    expect(ClientEnv.env()).toBe(GameEnv.Preprod);
+    expect(ClientEnv.numWorkers()).toBe(4);
+    expect(ClientEnv.turnstileSiteKey()).toBe("test-key");
+    expect(ClientEnv.jwtAudience()).toBe("openfront.dev");
+    expect(ClientEnv.instanceId()).toBe("TEST_ID");
     expect(fetchSpy).not.toHaveBeenCalled();
   });
 
-  test("maps staging builds to the default game logic config", async () => {
-    process.env.GAME_ENV = "staging";
+  test("throws when BOOTSTRAP_CONFIG is undefined", () => {
+    expect(() => ClientEnv.env()).toThrow(/Missing BOOTSTRAP_CONFIG/);
+  });
 
-    expect(getBuildTimeGameLogicEnv()).toBe(GameLogicEnv.Default);
-    expect(getServerConfigForGameLogicEnv(GameLogicEnv.Default).env()).toBe(
-      GameEnv.Prod,
-    );
+  test("throws when a required field is missing", () => {
+    window.BOOTSTRAP_CONFIG = {
+      gameEnv: "dev",
+      numWorkers: 1,
+      turnstileSiteKey: "k",
+      jwtAudience: "localhost",
+      // instanceId missing
+    };
+    expect(() => ClientEnv.instanceId()).toThrow(/Missing BOOTSTRAP_CONFIG/);
+  });
 
-    const config = await getGameLogicConfig({} as any, null);
+  test("jwtIssuer maps 'localhost' to http://localhost:8787", () => {
+    window.BOOTSTRAP_CONFIG = {
+      gameEnv: "dev",
+      numWorkers: 1,
+      turnstileSiteKey: "k",
+      jwtAudience: "localhost",
+      instanceId: "x",
+      gitCommit: "DEV",
+    };
+    expect(ClientEnv.jwtIssuer()).toBe("http://localhost:8787");
+  });
 
-    expect(config.serverConfig().env()).toBe(GameEnv.Prod);
+  test("jwtIssuer derives api.<audience> for non-localhost", () => {
+    window.BOOTSTRAP_CONFIG = {
+      gameEnv: "prod",
+      numWorkers: 1,
+      turnstileSiteKey: "k",
+      jwtAudience: "openfront.io",
+      instanceId: "x",
+      gitCommit: "abc123",
+    };
+    expect(ClientEnv.jwtIssuer()).toBe("https://api.openfront.io");
   });
 });