v0.14.2 — the preview works on real projects now

Found on the first real music video, an hour after shipping 0.14.0.

Final Cut Pro starts sequences at 01:00:00:00 by broadcast convention. So in an exported project, element offsets begin at 3600s — a 164-second timeline whose clips sit between 3600s and 3743s.

The preview assumed an origin of 0. It computed left: 2195% for the first block and clamped every one of them to the right edge, rendering a real project as a single stripe.

examples/sample.fcpxml starts at 0. That is the only reason the entire 0.14.0 test suite passed.

The origin is now derived from the earliest element, which handles a 0-based sequence, an hour-offset one, and anything else. It deliberately does not read tcStart — that attribute reads 0s on real projects whose clips nonetheless start at 3600s, so trusting it would have reproduced the bug.

Verified against the project that found it: 129 connected clips across lanes 1-14, now spanning 0.0% to 87.18%, none clamped.

Full Changelog: v0.14.1...v0.14.2