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/config.ts

@@ -0,0 +1,53 @@
+import { env } from '$env/dynamic/private';
+
+const DAY_SECONDS = 60 * 60 * 24;
+const DEFAULT_OIDC_SCOPE = 'openid profile email offline_access';
+
+function positiveInt(value: string | undefined, fallback: number): number {
+	if (value === undefined || value === '') return fallback;
+	const parsed = Number(value);
+	return Number.isInteger(parsed) && parsed > 0 ? parsed : fallback;
+}
+
+export const authConfig = {
+	get issuer() {
+		return env.ZITADEL_ISSUER;
+	},
+	get clientId() {
+		return env.ZITADEL_CLIENT_ID;
+	},
+	get clientSecret(): string | undefined {
+		const secret = env.ZITADEL_CLIENT_SECRET;
+		return secret && !secret.startsWith('REPLACE_') ? secret : undefined;
+	},
+	get scope() {
+		return env.OIDC_SCOPE || DEFAULT_OIDC_SCOPE;
+	},
+	get redirectUri() {
+		return env.AUTH_REDIRECT_URI;
+	},
+	get postLogoutUri() {
+		return env.AUTH_POST_LOGOUT_URI;
+	},
+	get sessionSecret() {
+		return env.SESSION_SECRET;
+	},
+	get sessionTtlSeconds() {
+		return positiveInt(env.SESSION_TTL_SECONDS, 7 * DAY_SECONDS);
+	},
+	get refreshThresholdSeconds() {
+		return positiveInt(env.SESSION_REFRESH_THRESHOLD_SECONDS, 30);
+	},
+	get flowTtlSeconds() {
+		return positiveInt(env.AUTH_FLOW_TTL_SECONDS, 600);
+	},
+	get allowInsecureHttp() {
+		return env.AUTH_ALLOW_INSECURE_HTTP === 'true';
+	}
+};
+
+export const apiConfig = {
+	get baseUrl() {
+		return (env.API_BASE_URL ?? '').replace(/\/+$/, '');
+	}
+};