feat(ui): give the app one visual identity as Movie Loop

Gold is the primary in both themes, Bricolage Grotesque carries the
wordmark, titles and the score, and Movie A / Movie B wear the blue and
magenta of three-strip Technicolor on their posters instead of colouring
whole rows. The loop closes on screen - connectors light, a gold line
draws back to Movie A, the row glows, then the result arrives - in place
of confetti, on every play mode, scaled to the chain's length. Every
page shares one header and hairline lists; copy is sentence case with
one verb per flow, and the Home hero shows a real finished loop.

Also clamps link counts at zero: an opponent who had not moved yet
showed "-1 links".

public/favicon.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#da950b" stroke-width="2.5" stroke-linecap="round"><path d="M20.5 12a8.5 8.5 0 1 1-3.63-6.96"/><circle cx="19.54" cy="8.08" r="1.75" fill="#da950b" stroke="none"/></svg>