refactor: rename frontend/ to web-player/ and format with prettier

Updates the compose build context, the Dockerfile header, the package
name and the docs. The compose service and container keep the name
frontend/musify-frontend, since nginx routes to http://frontend:3000.

The source files also carry the first prettier pass, so the rename and
the reformat land together for them.

web-player/src/lib/server/upload.ts

@@ -0,0 +1,110 @@
+import http from 'node:http';
+import https from 'node:https';
+import { env } from '$env/dynamic/private';
+
+const CONNECT_HOST = env.S3_UPLOAD_CONNECT_HOST || '127.0.0.1';
+
+export const IMAGE_TYPES: Record<string, string> = {
+	jpg: 'image/jpeg',
+	jpeg: 'image/jpeg',
+	png: 'image/png',
+	webp: 'image/webp'
+};
+
+export const AUDIO_TYPES: Record<string, string> = {
+	mp3: 'audio/mpeg',
+	m4a: 'audio/mp4',
+	aac: 'audio/aac',
+	flac: 'audio/flac',
+	wav: 'audio/wav',
+	ogg: 'audio/ogg',
+	opus: 'audio/opus'
+};
+
+export function extOf(name: string): string {
+	const dot = name.lastIndexOf('.');
+	return dot >= 0 ? name.slice(dot + 1).toLowerCase() : '';
+}
+
+export function contentTypeOf(file: File, table: Record<string, string> = IMAGE_TYPES): string {
+	if (file.type) return file.type;
+	return table[extOf(file.name)] ?? 'application/octet-stream';
+}
+
+export async function putPresigned(
+	presignedUrl: string,
+	body: Buffer,
+	contentType: string
+): Promise<void> {
+	const url = new URL(presignedUrl);
+	const signed = new Set(
+		(url.searchParams.get('X-Amz-SignedHeaders') ?? 'host').toLowerCase().split(';')
+	);
+
+	const headers: Record<string, string | number> = {
+		Host: url.host,
+		'Content-Length': body.byteLength
+	};
+	if (signed.has('content-type')) headers['Content-Type'] = contentType;
+	if (signed.has('if-none-match')) headers['If-None-Match'] = '*';
+
+	const secure = url.protocol === 'https:';
+	const transport = secure ? https : http;
+	const port = url.port || (secure ? 443 : 80);
+
+	await new Promise<void>((resolve, reject) => {
+		const request = transport.request(
+			{
+				host: CONNECT_HOST,
+				port,
+				method: 'PUT',
+				path: url.pathname + url.search,
+				headers
+			},
+			(response) => {
+				let raw = '';
+				response.on('data', (chunk) => (raw += chunk));
+				response.on('end', () => {
+					const status = response.statusCode ?? 0;
+					if (status >= 200 && status < 300) resolve();
+					else reject(new Error(`S3 PUT ${status}: ${raw.slice(0, 200)}`));
+				});
+			}
+		);
+		request.on('error', reject);
+		request.write(body);
+		request.end();
+	});
+}
+
+export type UploadImageResult = { intentId: string } | { failMessage: string; detail?: string };
+
+export async function uploadPresignedImage(
+	reserve: (args: { fileType: string; contentType: string; expectedSizeBytes: number }) => Promise<{
+		data?: { uploadUrl: string; contentType: string; intentId: string } | null;
+		error?: unknown;
+	}>,
+	file: File
+): Promise<UploadImageResult> {
+	const { data: reserved, error: reserveError } = await reserve({
+		fileType: extOf(file.name) || 'jpg',
+		contentType: contentTypeOf(file),
+		expectedSizeBytes: file.size
+	});
+
+	if (reserveError || !reserved) {
+		return { failMessage: 'No se pudo reservar la subida de la portada.' };
+	}
+
+	try {
+		const buffer = await file.arrayBuffer();
+		await putPresigned(reserved.uploadUrl, Buffer.from(buffer), reserved.contentType);
+	} catch (err) {
+		return {
+			failMessage: 'Falló la subida de la portada al almacenamiento.',
+			detail: err instanceof Error ? err.message : undefined
+		};
+	}
+
+	return { intentId: reserved.intentId };
+}