Show a live character preview beside the emote panel on hover

[darkdarkcocoa]

Summary

Hovering an emote row now shows the player's own character performing that emote in a small box beside the panel — inspired by the emote previews in Once Human and other MMORPGs. The preview renders the live character model with its equipped look, so what you see is exactly what everyone else will see.

Clicking a row performs the emote for real — the server broadcasts it to everyone nearby. Hovering costs nothing, so a player can check what a dance actually looks like, at portrait scale, before deciding to perform it in public; the top-down camera keeps the in-world character small, so the preview also doubles as a close-up of what everyone else is seeing.

Like the panel itself, the preview is fully derived from the server's emote list: it plays clips from social.glb by name, so a new server emote gets a working preview with zero extra client work — no per-emote images to produce or record.

How it works

• EmotePreview.svelte mounts a second small Threlte <Canvas> (own WebGPU renderer) inside the panel — the shared main canvas is busy rendering the world, so a self-contained canvas keeps its render pipeline untouched, the same approach CharacterPreview takes on the select screen. EmotePreviewScene.svelte loads the character model and the social animation pack through the shared GLB cache — everything is already in memory in-game, so there is no extra download.
• Clips play by name on an AnimationMixer, same as PlayerModel does in-world; one-shots loop in the preview so the motion stays readable.
• The box follows the hovered row, keeps the last emote playing when the pointer leaves, and hides while dead/disconnected or while the panel is being dragged.
• emote-preview-layout.ts decides which side of the panel has room (flipping right when the panel is dragged against the left edge) and hides the preview entirely on viewports where neither side fits (< 415 px), where it also skips mounting the canvas at all.

Performance notes

• The preview renders only while an emote is actually playing (manual invalidation), steps at the graphics preset's frame cap via the shared createRenderCadence, and takes its pixel ratio from the preset cap through the Canvas dpr prop.
• A dedicated createPreviewWebGPURenderer reuses the main renderer's applied antialias without touching the stored applied-AA record (which drives the settings panel's restart notice), and defers a dispose that races init() so the GPU device is actually released.

Testing

• npm test (client): 513 passing, including new placement tests covering the side flip and the narrow-viewport cutoff.
• npm run check / npm run lint: clean.
• Verified live: hover/switch/click-to-play, panel close/reopen, click-through over the hidden box, no console errors.