Daemon: child processes don't inherit merged env (breaks yt-dlp slides under launchd)

[heyalchang]

Bug

Slide extraction fails under the daemon with:

Slides stream failed: yt-dlp exited with code 1:
ERROR: [youtube] ...: Requested format is not available

The same summarize --slides command works perfectly from the CLI.

Root cause

When the daemon runs under launchd, process.env.PATH is minimal (/usr/bin:/bin:/usr/sbin:/sbin). The daemon builds a merged env from the daemon.json snapshot and threads it through internal code — resolveExecutableInPath() correctly finds yt-dlp using the merged PATH. But spawnTracked() (packages/core/src/processes.ts:146) spawns child processes without passing env in the spawn options, so they inherit process.env (the minimal one).

This means yt-dlp can't find deno on PATH. Since yt-dlp 2025.11.12 (yt-dlp/yt-dlp#15012), deno is required for YouTube JS challenge solving. When cookies are enabled (--cookies-from-browser), yt-dlp uses authenticated YouTube APIs that require JS challenges — without deno, format resolution fails silently.

Reproduction

# Simulates the daemon's launchd environment:
env -i PATH="/usr/bin:/bin:/usr/sbin:/sbin" HOME=$HOME \
  /opt/homebrew/bin/yt-dlp --cookies-from-browser chrome \
  -f "bestvideo[height<=720][vcodec^=avc1][ext=mp4]/best[height<=720][vcodec^=avc1][ext=mp4]/bestvideo[height<=720][ext=mp4]/best[height<=720]" \
  "https://www.youtube.com/watch?v=ZNL5wwflU-E" --no-download
# → ERROR: Requested format is not available

# Same command with full PATH (includes /opt/homebrew/bin where deno lives):
yt-dlp --cookies-from-browser chrome \
  -f "bestvideo[height<=720][vcodec^=avc1][ext=mp4]/best[height<=720][vcodec^=avc1][ext=mp4]/bestvideo[height<=720][ext=mp4]/best[height<=720]" \
  "https://www.youtube.com/watch?v=ZNL5wwflU-E" --no-download
# → works fine

Environment

• macOS 15 (Tahoe), arm64
• summarize 0.11.1 (Homebrew)
• yt-dlp 2026.2.4
• deno 2.6.9 (at /opt/homebrew/bin/deno)
• SUMMARIZE_YT_DLP_COOKIES_FROM_BROWSER=chrome set in daemon.json

Timeline

This is a latent issue that became visible through a combination of factors:

1. The daemon was designed to build a merged env for internal use, but never applied it to process.env — this was fine initially since the daemon wasn't spawning external tools.
2. Slides (d9ed602) introduced child process spawning (yt-dlp, ffmpeg). At that time yt-dlp didn't need deno, so the minimal PATH worked.
3. Cookie support for slides (3011970) made yt-dlp use authenticated YouTube APIs.
4. yt-dlp 2025.11.12 made deno required for JS challenges on authenticated APIs.
5. The combination of cookies + deno requirement + minimal launchd PATH triggers the failure.

Fix

PR incoming — applies the snapshot env keys to process.env in src/daemon/cli.ts before starting the server, so child processes inherit the correct PATH.