The cli, engine, and lint packages each carried their own copy of the
ffmpeg/ffprobe lookup, annotated fallow-ignore code-duplication, and the
copies had drifted: the engine copy handled Windows PATHEXT and executed
which/where without a shell but lacked the Homebrew-dirs fallback for
GUI-spawned processes; the cli copy had the opposite. One resolver in
@hyperframes/parsers (the dependency-graph bottom) now carries the union
of both hardenings, and all three packages delegate to it. Every
consumer gets strictly more robust resolution; env-override semantics
per call site are preserved via configuredMustExist.
## Problem
Windows renders commonly fail with environment errors before any real work starts:
- `Browser was not found at the configured executablePath (...chrome-headless-shell.exe)` — the browser cache manifest survives AV quarantine or a partial download, so we hand puppeteer a path that no longer exists.
- `[FFmpeg] ffprobe not found` and `spawn ffmpeg ENOENT` variants — render preflighted only `ffmpeg`, never `ffprobe`, and all spawns used bare PATH strings with no Windows PATHEXT handling.
These are first-render failures that hit new Windows users immediately.
## Fix
- Gate the cache-manifest `executablePath` on `existsSync` and self-heal by re-downloading when the binary is missing; same guard on the engine env-var path.
- New shared environment preflight (`packages/cli/src/browser/preflight.ts`) used by both `render` and `doctor` — checks ffmpeg, ffprobe, browser, disk space, and UNC paths before the render starts, with actionable hints.
- Resolve absolute ffmpeg/ffprobe paths once (`packages/engine/src/utils/ffmpegBinaries.ts`) and pass them to every engine spawn instead of relying on PATH.
- Map opaque Windows ffmpeg exit codes to actionable messages.
## Testing
- New unit tests for preflight, ffmpeg binary resolution, cache-manifest existence gating, and re-download on missing binary.
- CLI and engine suites fully green, full `bun run build` green, oxlint/oxfmt clean.
- Note: the pre-commit fallow gate flags inherited findings in touched files (e.g. `audioExtractor.ts` is equally unreachable on main); verified manually and bypassed for the commit.
Miguel Angel Simon Sierra