[Medium] deleteSession can race in-flight background post-processing

Severity

Medium — race between deletion and background work; can corrupt/partially write into a deleted session dir.

Location

• electron/ipc.ts:196 (deleteSession handler) validates sessionId and refuses deletion only while the session is actively recording (lines 198–199) — it does not account for post-processing.
• electron/recorder/controller.ts:517 (schedulePostProcess) runs describer/frame work after stop() returns, in the background.

Mechanism

Right after Stop, post-processing (analysis, frame extraction) is still running for the session. Nothing prevents the user from deleting that same session in the same window, so background tasks can write frames/analysis into a directory that deleteSession is concurrently removing.

Impact

Orphaned/partial files, write-after-delete errors, or a resurrected half-session directory.

Suggested fix

Track in-flight post-processing per session id; have deleteSession cancel (or await) it before removing the directory — or refuse deletion with a clear message while post-processing is active (mirroring the active-recording guard).

Regression test to add (npm test)

Unit test: start a fake post-process task for a session, call deleteSession while it's pending, and assert the delete either cancels/awaits it and that no write lands after the directory is removed. Deterministic; not an evals/ concern.

Start with the deleteSession handler in electron/ipc.ts around line 196 and schedulePostProcess in electron/recorder/controller.ts around line 517. Run npm test and add the described deterministic unit test with a pending fake post-processing task. Done means deletion safely cancels or awaits post-processing, with no write occurring after the session directory is removed.