Opening cutscene as video, guest tutorial, popup queue (3.5.0)

The opening cutscene moves from static panels to video. Thirteen panel-sized MP4 clips replace the previous still-image flow, with their own soundtrack underneath and a corner skip control so anyone who's seen it can jump past. The cutscene system grew an expo-video runtime, a cascade resolver, a showcase view, and a videoAssetMap that registers and serves the panel assets. Web needed a few render fixes; native added a polygon clip so the panel edges match the cutscene frame.

Guest tutorial flow is in. The first-mission tutorial used to require sign-in before you could start — that gated curious players behind an auth step. The tutorial now runs as a guest, with sign-in moved to Ormron Street after the briefing. The 401 that was firing on the old Start Tutorial button is resolved.

Popups got a unified queue. Two popups used to be able to render at once and step on each other; the queue now allows one Modal at a time, priority-ordered so important popups (sigil unlocks, rewards) take precedence over softer ones. Sigil-unlock popups got their own polish pass — the celebratory card always shows now, and notification cursors track per-player so the same unlock card doesn't replay.

Two small fixes: tutorial highlights on hub triggers now render correctly (the zone style was being dropped on the wrap helper), and Olija + Nell triggers on Ormron Street got nudged 20px up so the heroes don't overlap the trigger zones visually.