Remove a customer's video from disk once its frame is read

[singhharsh1708]

Customer problem

Every video a customer attaches is left on the server's disk. extractVideoFrame writes the clip and the frame into a new temp folder (vec-…) and never removes it, whether a frame came out or not. That is up to 8 MB of a customer's attachment per video, kept until the container is replaced.

Change

The folder is removed in a finally block, so it goes on success, on an ffmpeg failure and on a throw.

Evidence

The frame is returned in memory and nothing reads the folder afterwards, so there is no reason for the clip to stay. The text attachment path keeps nothing on disk either.

Verification

• Added or updated a focused behavior test: one in test/attachments.test.js runs the real frame step on a clip that is not a video and checks no vec- folder is left. It fails on main with the folder still there
• npm test: 627/627
• EVAL_NO_MODEL=1 node scripts/customer-eval.js: 8/8
• Live-model evaluation not needed: no prompt, routing or model path changes
• No secrets, customer PII, .env, or railway.toml
• No new claim that a person was pinged, an issue was filed, or an email was sent without confirmed success