feat: full-screen embedded show UI, and speed + fade as the fixed master sliders

[pyramation]

Summary

Two artist-facing complaints: the embedded show UI is a postage stamp inside the desktop panel, and the top bar's permanent sliders are the ones nobody touches mid-show.

Full screen. ShowRoute keeps an expanded flag; when set it renders fixed inset-0 with only a thin exit bar above the slot. Nothing about the embedded UI changes — it is a native WebContentsView that simply follows whatever bounds the renderer reports, so "full screen" is just a bigger rectangle:

-  }, [running, url, overlay]);
+  }, [running, url, overlay, expanded]);   // the slot moved; re-measure it

The subtlety is Escape. While the embedded UI fills the window it holds focus, so the renderer's keydown listener never fires — the keypress lands in the embedded web contents. laser-view intercepts it there and forwards it:

created.webContents.on('before-input-event', (_e, input) => {
  if (input.type === 'keyDown' && input.key === 'Escape') win.webContents.send('laser:escape');
});

surfaced as window.wavegridLaser.onEscape(handler) → unsubscribe. The exit button exists too, so there is a mouse way out even if that plumbing breaks.

Master sliders. The fixed slots become Speed and Fade; Bright and Attack move behind a ⋯ disclosure (and remain in the phone's expandable panel unchanged). Speed is the same 0.01x–5x logarithmic control the tool panel already had, so slider entries now carry a display string rather than being assumed to be a 0–100 integer:

{ label: 'Speed', value: speedToPct(animSpeed), display: '1.0x', handler: (pct) => onAnimSpeed(pctToSpeed(pct)) }

It drives the existing handleAnimSpeed → { type: 'anim_speed' }, so it is the same value as the tool panel's Speed slider, not a second one.

Link to Devin session: https://app.devin.ai/sessions/ec43152136134467a853ec0bbf783ea9
Requested by: @pyramation

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