[Bug]: Click sounds play only for the first clip of a recording, not for a duplicated clip #1146

Summary

With the Cursor facet's Mouse clicks on, a duplicated clip of the same recording (copy/paste, #1011) plays no click sounds, in the export or in the preview. Only the first clip that uses the asset gets them.

Repro

1. Record a take with a few clicks.
2. Turn on Cursor > Mouse clicks.
3. Copy the clip and paste it after itself (optionally trim the copy, add a speed region to each).
4. Export, or play the second clip in the preview.

Evidence (v2.1.0 candidate, build 38252812147, macOS 26.5 arm64)

• Project: clip 1 = source 0 to 37.78 s, clip 2 = duplicate trimmed to source 0 to 8.8 s, a 1.5x speed region on each clip at source 1.989 to 3.918 s.
• Telemetry clicks at source 6.679, 10.91, 15.105, 29.244, 37.568 s.
• Export (720p 30 fps): high-passed transients at 6.04, 10.26, 14.44, 28.59, 36.91 s, all clip 1 after the speed mapping (within 20 ms). Clip 2's click at source 6.679 s, expected at 43.17 s, is missing.

Cause

clickPlacement in src/lib/ai-edition/clickSound.ts walks the clips of the take and returns on the first one whose kept source window contains the click, so every click gets at most one placement. The export's hits and the preview's per-clip cue buckets both come from that one placement, so the copy gets nothing in either.

Expected

A click plays once for every clip whose kept source range contains it, at the programme time that clip's trims and speed regions give it (the checklist row: "none from a trimmed-out span, at the timing a speed region gives them").

Actual

Only the first clip of the asset plays its clicks.