spoolcast SFX — meme/reaction audio per chunk
non-voice audio (stingers, reactions, broll burned audio) wired into the spoolcast chunk schema and remotion mix — fixes silent-meme dead-air
extend the spoolcast audio pipeline so meme, reaction, and broll chunks can carry non-voice audio. today every chunk expects TTS narration tied to its beats; silent meme chunks pause the video awkwardly (caught on dev-log-02, flagged again on dev-log-03 — confession ding, meta-beat punchline sting, "noticing" reaction, and act bumper transitions all wanted SFX but shipped without). starter scope: 20–30 SFX clip library covering common reaction registers, new chunk field sfx (path to short audio file), validator pass so silent-hold chunks must have either sfx or a documented exception, preview-data + remotion composition update to mix the audio alongside narration. spec lives in spoolcast/ROADMAP.md §6.