fix: preserve ${VAR} interpolation in .env files

Escaping in prepareEnvironmentVariablesForFile escaped every $,
including inside a deliberate ${VAR} reference, breaking Compose's
documented .env variable interpolation. Only escape $ that isn't
part of a ${IDENTIFIER} sequence.

Fixes #5151

apps/dokploy/__test__/compose/env-file-literals.test.ts

@@ -32,6 +32,8 @@ const cases: Record<string, string> = {
 	APOSTROPHE: "it's a test",
 	UNICODE: "héllo wörld 日本語 🚀",
 	MULTILINE_PEM: "-----BEGIN KEY-----\nabc123\n-----END KEY-----",
+	APP_URL: "https://example.com",
+	ASSET_URL: "https://example.com",
 };
 
 // How each value must be typed in the UI so the (unchanged) dotenv input
@@ -46,6 +48,8 @@ const inputEncoding: Record<string, string> = {
 	APOSTROPHE: "it's a test",
 	UNICODE: "héllo wörld 日本語 🚀",
 	MULTILINE_PEM: '"-----BEGIN KEY-----\nabc123\n-----END KEY-----"',
+	APP_URL: "https://example.com",
+	ASSET_URL: '"${APP_URL}"',
 };
 
 describe("getCreateEnvFileCommand", () => {

packages/server/src/utils/docker/utils.ts

@@ -548,7 +548,7 @@ export const prepareEnvironmentVariablesForFile = (
 		const escapedValue = value
 			.replace(/\\/g, "\\\\")
 			.replace(/"/g, '\\"')
-			.replace(/\$/g, "\\$");
+			.replace(/\$(?!\{[A-Za-z_][A-Za-z0-9_]*\})/g, "\\$");
 		return `${key}="${escapedValue}"`;
 	});
 };