fix(player): reject non-finite composition dimensions from attributes and stage-size (#1205)

width/height attributes went through parseInt with no validation, so a
typo like width="abc" reached scaleIframeToFit as NaN (invalid
scale(NaN) transform) and width="0" as a division by zero — both
blank the player with no signal. The stage-size message check had the
sibling gap: `> 0` alone lets Infinity through, which scales the
iframe to 0.

Reuse the composition probe's readPositiveDimension guard for the
attribute path (the probe path already rejected these) and add the
same finite-check the adjacent timeline branch uses for stage-size.
Mirrors the clampPlaybackRate hardening from #1120.

Co-authored-by: Carlos Alcaraz <193642530+calcarazgre646@users.noreply.github.com>

packages/player/src/composition-probe.ts

@@ -36,7 +36,15 @@ export interface ProbeCallbacks {
   onRuntimeInjected?: () => void;
 }
 
-function readPositiveDimension(value: string | null): number | null {
+/**
+ * Parse a composition dimension, rejecting anything that isn't a positive
+ * finite number. Exported because the `width`/`height` attribute handlers in
+ * hyperframes-player.ts need the same guard: dimensions feed
+ * scaleIframeToFit's `w / compositionWidth` division, where NaN produces an
+ * invalid `scale(NaN)` transform and zero a division by zero — both render
+ * the player blank with no signal.
+ */
+export function readPositiveDimension(value: string | null): number | null {
   if (value === null) return null;
   const parsed = Number.parseInt(value, 10);
   return Number.isFinite(parsed) && parsed > 0 ? parsed : null;