Scaffold backend (FastAPI/uv) and frontend (SvelteKit/bun)

Backend: FastAPI app with health check, AppError hierarchy, stderr
logging via LOG_LEVEL, ruff+pyright(strict) config, pytest passing.

Frontend: SvelteKit (TS) with prettier, eslint, vitest (unit +
component), adapter-node for self-hosted deployment on Zeus.

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/prettier.config.js

@@ -0,0 +1,11 @@
+/** @type {import("prettier").Config} */
+const config = {
+	useTabs: true,
+	singleQuote: true,
+	trailingComma: 'none',
+	printWidth: 100,
+	plugins: ['prettier-plugin-svelte'],
+	overrides: [{ files: '*.svelte', options: { parser: 'svelte' } }]
+};
+
+export default config;