feat: phase 0 foundation — monorepo scaffold, backend, frontend, CI, docker

Establishes the skeleton every later phase builds on: Go+Gin API with
zap logging, /api/healthz, SQLite+goose runner; Vite+React18+TS strict+
Tailwind v4 frontend with bento-mono theme tokens; openapi.yaml driving
a generated TS client; oxlint with vendored anti-slop rules; GitHub CI;
multi-stage Dockerfile -> 33.6MB distroless image; docker compose up
serves the blank board.


Generated with [Devin](https://devin.ai)

Authored By: TDvorak <[email protected]>
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/frontend/src/main.tsx

@@ -0,0 +1,16 @@
+import "@fontsource-variable/geist";
+import "@fontsource-variable/geist-mono";
+import "./index.css";
+
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import App from "./App.tsx";
+
+const root = document.getElementById("root");
+if (!root) throw new Error("#root missing");
+
+createRoot(root).render(
+	<StrictMode>
+		<App />
+	</StrictMode>,
+);