fix(launch): skip script concatenation for projects with esm scripts

[kpal81xd]

Problem

Launching with Concatenate Scripts (Classic) enabled (concatenateScripts=true) hangs the launcher — it never finishes loading — for any project that contains ESM (.mjs) scripts.

Script concatenation is a classic-scripts-only backend feature. When the project also has ESM scripts, the /api/projects/:id/concatenated-scripts/scripts.js endpoint times out:

Failed to load resource: the server responded with a status of 504 ()
Script: .../concatenated-scripts/scripts.js?branchId=... failed to load

Every preloaded classic script points at that URL, so the engine's preload blocks on the failing request and the loading screen stalls until the gateway times out.

Fix

Guard concatenateScripts=true at its single source (launchApp in viewport-launch.ts): don't request concatenation when the project contains any ESM script. Evaluated fresh on each launch, so it tracks scripts added/removed mid-session, and the && short-circuits so the asset scan only runs when the option is checked.

Notes / trade-offs

• Mixed classic+ESM projects lose classic-script concatenation entirely — forced by the backend, which 504s on the whole bundle when any ESM script is present.
• A hand-typed ?concatenateScripts=true URL still bypasses this; the launcher can't reliably detect ESM before it routes assets. The real cure there is the backend not 504-ing.

Testing

• eslint clean on the changed file; typecheck introduces no new errors (pre-existing baseline unchanged).
• Not exercised end-to-end (requires a project with ESM scripts against the live launch backend).

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Project	Deployment	Actions	Updated (UTC)
editor	Ready	Preview, Comment	Jul 9, 2026 1:25pm

[kpal81xd]

Closing: investigation of the backend (monorepo) shows the concatenation service already excludes ESM (.mjs) and concatenates classic .js scripts only — this has been the deployed behavior since #2537 (2024-10-01). So disabling concatenation client-side for any project containing ESM scripts is over-broad: it removes a working optimization for the classic scripts in mixed projects, and doesn't address the actual cause of the 504 (the launch concatenated-scripts/scripts.js endpoint blocks the HTTP request on an on-demand generation job with no timeout, so a cold-cache miss can trip the gateway timeout). Fixing this properly on the backend instead.