desloppify: code health overhaul plus abuse hardening (140 green, strict 87.2)

Honest baseline after removing 45 gaming suppressions. Structural: lib/game plus root hooks extraction, CORS origin echo, DEV_ORIGINS layering. Fixes: error-cause binding, discord 5xx split, null-cache guard, co-located tests, rejecting-fetch coverage, naming and typing cleanup, socket controller, cache bound, cascade helpers, latch resets. Hardening: per-IP rate limit on API routes, deterministic-miss UX, retry cooldown plus cap. Suite 140 green, build plus lint clean.

app/page.test.tsx

@@ -0,0 +1,51 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { render, screen } from "@testing-library/react";
+import Home from "@/app/page";
+
+vi.mock("@/lib/i18n/get-locale", () => ({
+    getLocale: async () => "en" as const,
+}));
+
+afterEach(() => {
+    vi.unstubAllGlobals();
+});
+
+describe("Home page", () => {
+    it("renders hero, sections, and footer", async () => {
+        vi.stubGlobal(
+            "fetch",
+            vi.fn(async (url: string) => {
+                if (String(url).includes("git.fristy.net")) {
+                    return { ok: true, json: async () => [] } as Response;
+                }
+                return {
+                    ok: true,
+                    json: async () => ({
+                        success: true,
+                        data: {
+                            discord_user: {
+                                id: "1",
+                                username: "testuser",
+                                global_name: "Test User",
+                                display_name: "Test User",
+                                discriminator: "0",
+                                avatar: null,
+                                bot: false,
+                            },
+                            activities: [],
+                            discord_status: "offline",
+                            active_on_discord_desktop: false,
+                            active_on_discord_mobile: false,
+                            active_on_discord_web: false,
+                            listening_to_spotify: false,
+                            spotify: null,
+                        },
+                    }),
+                } as Response;
+            }),
+        );
+        render(await Home());
+        expect(screen.getByRole("heading", { level: 1 }).textContent).toBe("fristy");
+        expect(screen.getByText("@testuser")).toBeDefined();
+    });
+});